Category Archives: Rifles

RELOADERS CORNER: Problems Dies Can Have

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Reloading problem? First make sure it’s not your tools… Here are a few things that can happen, and how to correct them.

Glen Zediker

Over years and years (and years) I’ve encountered a few factory-faulty sizing and seating dies, and associated pieces-parts. It’s not at all common, but it happens, or has happened, enough that I wanted to share a few stories as to what these problems come from, and how to identify (and correct) them.

As has been my norm here of late, yep: got a phone call from a fellow having problems with a new 28 Nosler. Took a while to get through this one… Turned out that the sizing die was the culprit. Wasn’t easy to sleuth but there’s a Zen tenet that paraphrases to this: If you’re not sure what something is, then carefully consider all the things that it is not; what’s left is the answer…

forster concentricity fixture
A concentricity fixture is a handy tool to help identify any issues a sizing or seating die has.

By the way, I’m not going to mention brand names for one good reason: I’ve seen or been presented with issues in dies from every major maker.

Sizing die problems I have either encountered first-hand or been witness to via my circle have most often been a full-length die that will not adequately set a case shoulder back where we want to take it. Conversely, it’s much more common to have a die that’s erring on the more extreme end of that, and erring toward “too much” sizing potential is logically a direction a die maker might take to accommodate more circumstances. Once the shellholder is making full and flush contact with the die bottom, that’s all she wrote. Continuing to turn the die body downward does nothing but stress the press and possibly damage the die. To get the case farther up into the die, either thin the shellholder top surface or grind the bottom of the die hisself. Neither are hand-tool operations! Get to a local gunsmith or machinist.

Look at a hair from your head and that’s ballpark 0.004-0.006 inches. It doesn’t take much at all to make the difference between smooth function and a bolt that won’t close.

loaded round runout
Check loaded rounds to point out bullet seater problems. Check sized rounds to point out sizing die issues. Removing the expander and checking neck runout on a sized round usually points out any problem with the die itself. It should spin with no to very little runout.

Check out Midsouth tools HERE

Most sizing dies are reamed one-piece, one-shot like a rifle chamber; however, that’s not always the method. Some are done in two or more steps, using two or more cutting tools. Clearly, consistency and correctness favors the one-piece reamer. Assuming that the reamer is correct and correctly used. I have encountered one die that just wasn’t concentric, body chamber to neck area. I figured that one out by sizing without the expander and checking runout, and also by finding that I could shift off-center axis by rotating the (marked) case and running through again. Normally, sizing a case without the expander in place results in a case that runs flat-line on a concentricity fixture. Reason is primarily because any inconsistency in the case neck walls get “pushed” to the inside case neck. But if there’s wobble in a case that’s been sized sans expander, then, son, you got a die problem.

A bent or bowed expander stem will, not can, result in an expander that’s going to cock the case neck one direction. I watch for that when I polish the expander button. As described here before, that process involves chucking the stem (lightly) in an electric drill and spinning the ball against some wet emery to give the ball a shine. If it’s wobbling during this operation, that’s a problem.

polished expander
With one particular brand of bullets (which were a tad amount smaller diameter than usual) I experienced inadequate bullet grip, insufficient to retain the bullet in the case neck on magazine-fed rounds. That wasn’t really a die problem, but the (simple) solution was to reduce the expander ball diameter. The die maker replaced the stem assembly for me so I didn’t have to apply that extra tension to rounds loaded with my usual bullet brand. When you polish the expander (and you will do that right?) notice if there’s wobble. Don’t accept it.

Seating die issues, in my experience, usually revolve around plain old straightness of the seating stem, and, once, the concentricity of the reamed case body area. If you have a seating die that increases runout compared to what a concentricity fixture showed on the sized case neck, it needs looked into. Additionally, always (always) check to make sure the seating plug (the area that fits over the bullet to push it into the case neck) is deep enough the the bullet tip does not make contact with the inside of the plug. That’s a sure way to get a bullet tipped off kilter.

bullet seating stem check
Always check to see that the tip of the (longest) bullet you use doesn’t contact the inside of the seating die plug. If it does it will get skewed.

Now. Most importantly: What to do if you suspect a tooling problem? Short answer is: SEND IT BACK. Don’t accept it. I know of no maker who won’t profusely apologize and promptly return a new one. The fixes I mentioned are for those who prefer to solve such issues, and also for those who have the means to effect repairs. The point to this article mostly is to be aware that problems can and do exist, and don’t accept them, whichever direction you seek for the solution.

No matter how precisely a die maker produced the parts, there is and will be some gap in threaded pieces. This can disguise itself as a “die” problem, but it’s really not. It’s a set-up problem. I did an article a good while back here on a few ideas on improving tool/case alignment via some set-up tricks, and maybe that should be the next topic under the Reloaders Corner banner.

The information in this article is from Glen’s newest book, Top-Grade Ammo, available HERE at Midsouth. Also check HERE for more information about this and other publications from Zediker Publishing.

 

SKILLS: Riflescopes: Adjustments & Variable Power

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There’s a lot to learn to really understand riflescopes and make the best choice. Here’s another valuable lesson. Keep reading…

riflecope

SOURCE: NRA Staff

Windage and elevation adjustments in riflescopes are made with either internal or external adjustment systems. Here’s what that means.

Internal: Most modern telescopic sights have internal adjustment systems using threaded, cylindrical knobs or screws in the turrets. The adjustment screws move the reticle assembly in the optical axis inside the main tube against spring pressure. The adjustment screws have clearly marked graduations around their circumference and many have a ball-detent system that clicks as the adjustment screws are turned. Each graduation or click represents a change in reticle position that moves the bullet strike at the target. This is expressed in minutes of angle (m.o.a.) and normally has a value of 1/2, 1/4 or 1/8 m.o.a. per click.

External: Many older scopes have an external-adjustment system built into the mounts and rings. Such scopes remain popular today for certain types of target competition. In this type of scope, the reticle remains stationary within the main tube and the point of the bullet strike is adjusted by mounts having micrometer windage and elevation mechanisms that move the entire scope laterally and/or vertically. These mounts often allow the scope to slide fore and aft to reduce recoil. An advantage of external-adjustment scopes is that the user is always sighting through the optical center of the tube.

As internal-adjustment systems became more reliable and more accurate, the popularity of external-adjustment scopes faded. Today, external-adjustment models are still offered, however the use of such scopes is now generally limited to a few specialized disciplines of rifle competition.

It is important to note that some scope-mounting systems designed for internal-adjustment scopes still incorporate the ability to accommodate some coarse external windage adjustment.

This leads us to the discussion of variable power. Variable-power riflescopes have an internal mechanism to change the amount of magnification within design limits. This consists of an additional set of lenses mounted in an internal tube that slides forward and rearward under the control of a cam attached to the magnification ring. The design of the lens system and its position in the tube controls the amount of magnification.

The popularity of variable-power riflescopes rests squarely on their flexibility. Variable magnification enables the shooter to adjsut the power to suit a wide variety of conditions ranging from lower power (with a wide field of view for fast shots at close range), to higher power (for greater precision at long range). Once considered expensive and unreliable, variable-power riflescopes have become the most popular type as their design has matured and prices have dropped. Todya, the single most popular riflescope is the 3-9X-40mm, which has become a kind of “jack of all trades.” Smaller variables such as 2-7X-32mm remain popular for smaller-caliber rifles, while 4.5-12X-50mm and bigger models are favored for long-range shooting. Despite their flexibility, no one variable fits all applications and that is why there are so many different models.

Despite their popularity, variable-power riflescopes may suffer from certain drawbacks:
ONE: The variable magnification system introduces another level of mechanical complexity and another source for optical error, potentially decreasing reliability.

TWO: The movement of the internal components of a variable-power scope can produce changes in zero as the scope power is increased or decreased.

THREE: Variable-power scopes are harder to seal than fixed-power scopes by virtue of the magnification-adjustment ring.
As the magnification increases, the field of view and image brightness decrease, often substantially.

FOUR: Variable-magnification scopes are substantially heavier than fixed-power scopes.

FIVE: Variable-power scopes are more expensive than fixed-power scopes.

Review: IWI Galil ACE Rifles

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Not only is the Galil ACE an updated version of the AK-platform rifles, it’s an updated version of itself. And one very capable rifle series. Read the full review…

Galil ACE

SOURCE: NRA: Shooting Illustrated, originally by Steve Adelmann

As a young gun enthusiast, I did’t pay much attention to the Kalishnikov family of firearms. That wasn’t due to any bad experiences with AKs, but rather because I had no experience with them whatsoever. In those days, when the Vietnam War was still a fresh memory that our parents were trying to forget, the Kalashnikovs were either disdained or ignored all together by my shooting influences. There were no commercially-available AK-based variants available here in the U.S. until the Finnish-made Valmet M62S, first imported as a legal-to-own rifle in 1970, and thereafter the Egyptian-made Steyr/Maadi.

The Valmet, like the IWI Galil line reviewed here, improved and updated the basic AK design. The Valmet provided such upgrades as buttstocks better suited to larger-statured people, synthetic furniture, and good iron sights. I read everything I could find on the M62, which wasn’t much in those pre-internet days, but the search nonetheless led me to the Israeli-made Galil family of firearms. Here was a design that incorporated the best of the AK and Valmet features in one platform. Most commonly chambered in 5.56 NATO and carried in near-daily conflict by Israeli troops, the Galil made frequent appearances in my adolescent daydreams.

Most mid-20th-century fighting-rifle designs that have endured into the new millennium have also been upgraded to meet evolving needs. The modern Galil is no exception. It comes to us now as the ACE platform, courtesy of Israel Weapon Industries (IWI). The Galil ACE is offered in two pistol and two rifle configurations. Both pistols are chambered in 7.62x39mm and use 8.3-inch barrels. The only discernible difference between them is that one model has a stabilizing brace and the other does not. One rifle is likewise chambered for the Russian cartridge, while the other is designed around the longer 7.62 NATO. IWI’s U.S. product literature also shows new-for-2017 pistol models chambered in 7.62 NATO and a 20-inch 7.62×39 mm. Several 5.56 NATO models were also introduced at the SHOT Show in January. All Galil ACE models carry the same improvements over the old Galil models like a smaller (left-side) charging handle, reduced iron-sight profiles, magazine commonality with other popular platforms, and integral Picatinny rail mounting surfaces.

IWI Galil ACE 7.62 NATO
IWI Galil ACE 7.62 NATO.

One important note: all members of the Galil ACE rifle family are assembled in the U.S. from a combination of American-made and imported parts to stay in compliance with 18 USC§922(r).

I recently tested two Galil ACE rifles, and in spite of their different chamberings and receiver sizes, these modern Galil incarnations share many common features. The ACE’s reciprocating charging handle is manipulated through an easy-to-grab knob protruding through the receiver’s left side. A spring-loaded cover plate positioned below the charging handle’s slot moves down and out of the way as the handle moves rearward, then closes up to protect internal parts as the bolt moves back into battery. A polymer pistol grip that’s molded into a larger plastic section that is attached to the receiver does not appear to be interchangeable with either AR or AK aftermarket parts.

IWI Galil ACE 7.62x38mm
IWI Galil ACE 7.62x39mm.

Right-side-folding stocks have the added ability to extend or collapse to any of six positions. Each rifle includes a polymer cheek piece that snaps over the buttstock for use with high-mounted optics. The rest can be attached in one of two positions on the stock to better fit the shooter.

Galil ACE buttstocks
(left) A proprietary yet familiar-looking buttstock is shared by both platforms. (right) Standard on the 7.62 NATO variant, an extended rubber butt pad is an accessory for the 7.62x39mm rifle.

The ACE’s forend has a very stout, aluminum, assembly that provides rails at the 3-, 6- and 9-o’clock positions. Each section is protected by a textured, sliding cover. The 6-o’clock cover has a slight bump at the front edge that should function as a sort of handstop for the pistol variants. Recesses are milled into the front of each aluminum rail section to allow pressure switches and cables to be inset into the forend; covers can then be reattached while providing access to the accessory buttons beneath them. The outer diameter of the fore-end with rail covers attached is a tad wide for my liking at 2.3 inches. The bare-aluminum rails are pretty tough on skin, and a set of silicone, aftermarket covers would be wise addition.

Galil ACE lower receivers
Subtle differences in the lower receiver distinguish these two Galil ACEs. Note the variances in pistol-grip shape, the location and type of magazine-release actuator, and in the trigger-guard geometry.

Milled-steel receivers and stamped-steel gas cylinders are topped by linked sections of Picatinny rail. The gas cylinder’s bottom surface slides into receiver slots, but it still has some play when fully seated. Thanks to a stout return spring, the receiver cover is held under enough tension to keep it (and the rail attached to it) very snug. A set of robust iron sights are protected by steel ears on each of the ACEs I tested. A massive front-sight post is easy to spot through either of the rear apertures, and the larger hole and front post come standard with tritium inserts. An included sight-adjustment tool moves the rear sight for windage and the front sight for elevation ala those of the AR family (a bullet tip will work, too). Front sight housings are transverse pinned to dovetails in the barrel and double as gas blocks (also AR-style). They are positioned at the front end of each rifle’s handguard and provide seats for the gas cylinders to mate with.

There are multiple sling-attachment loops, including one on the left side of the folding stock hinge. The right-side folder covers the selector on that side when fully closed, which is right where it stays until needed. The stock quickly deploys into a rock-solid extended position.

Internally, the Galil ACE rifles are very much AK-like in basic design. The long-stroke piston’s chrome-plated operating rod is affixed to the bolt carrier and the bolt itself is assembled into the carrier just like the rest of the AK family. Likewise, the trigger and hammer assemblies appear to be quite Kalashnikovian in design. Both test ACEs had very long trigger pulls that stacked up quickly to the 6-pound, 9-ounce average measured on both rifles.

A small selector lever is present on the receiver’s right side in the familiar Galil location. This lever is positioned so that a right-handed shooter can actuate it with the right forefinger. We lefties are out of luck on that side, but the ACE’s left-side selector was retained from the older model Galils. The positioning just above the pistol grip is best-situated for righties, but a left-handed shooter can either bring the firing thumb over to the left side or use the trigger finger to manipulate the selector. Neither technique is great, but proficiency is possible with practice. Still, a more ambidextrous design would be nice to see in this 21st-century upgrade.

Both rifles fieldstrip the same as any other AK variant. The main difference I found was that the return spring’s guide-rod end protrudes through the rear of the receiver cover much farther than the small button on the back of a standard AK. This button locks very positively through the receiver cover and is a solid way to ensure the receiver cover stays in place. Traditional AK receiver covers are notorious for popping off when the rifle takes a hard hit or is in close proximity to a blast.

Because the rear of the Galil ACE’s receiver and stock hinge are higher than the line of bore, they should be cleaned from the muzzle rearward.

Fire-Proofing
These rifles are clearly intended for rough-and-tumble fighting roles, but I wanted to note accuracy potential just the same. So, the first shooting was conducted with a magnified riflescope mounted. The ACE’s fixed iron sights are sufficiently high that many one-piece scope mounts will not clear them. The rear sight is removable, but I wanted to leave it intact as designed, so I used an old backup scope mount that sits much higher than my normal rings. I also attached the snap-on cheekpiece to better align my shooting eye with the scope. For close-in work, I brought along a Meprolight Tru-Dot RDS Pro optic. As high as the fixed sights are, they do not co-witness with any of the red dot/reflex sights I have, so I planned to test the irons with no optics attached.

Galil ACE details
(left) An A2-style “birdcage” flash hider caps the barrel of the 7.62x39mm Galil, while the 7.62 NATO ACE has a muzzle brake for recoil mitigation. (right) Unlike most AK variants, the rear sight is at the very back of the solid receiver cover, much better!

After cleaning and lubricating both rifles, I gathered three different ammo types per gun and headed out. Relatively lightweight bullets were chosen for testing the 7.62 NATO-chambered Galil ACE model, due to the 1:12-inch barrel twist rate.

The 7.62x39mm was first on the line and also presented me with my only functional problem. One of the loads I selected for this gun was Golden Tiger, steel-cased 123-grain FMJ-BT. This Russian-made ammo is usually accurate, but the primers are notoriously hard to detonate reliably in anything other than AKs. Well, despite its lineage, the Galil ACE experienced an 80-percent failure-to-fire rate. That is in no way the rifle’s fault — this ammunition is just plain difficult. After hand-cycling through about a dozen rounds to get the scope on paper, I dropped this problematic ammo and moved on.

The 7.62x39mm recoil was predictably tamer than that of its big brother and was helped along by a synthetic rubber buffer installed on the return-spring guide. Shooting groups with the long, stiff triggers was difficult with each rifle. They tended to shoot three shots in five in a respectably tight group with two shots typically going wide. I attribute that to the triggers, or rather my manipulation of them. Neither of these rifles was a tack-driver out of the box. Fortunately, ALG Defense debuted a purpose-built trigger for the Galil ACE rifle and pistol platforms during the 2017 SHOT Show. I have not laid hands on one, but if it is anything like the company’s AKT family of AK triggers, the new AGT will be worth every penny paid for the retrofit. Overall grouping tended to hover around 2 MOA, which is about what I expected considering their lineage and design.

Galil ACE magazines, forend
(left) Magpul supplies magazines for both Galils, with the PMag AKM feeding the 7.62x39mm ACE and a Gen 3 LR/SR25 PMag for the 7.62 NATO. (right) Sliding rail covers allow purchase on the quad rail handguard at the 3-, 6- and 9-o’clock positions. A handstop cover is provided on the bottom rail. Interesting note: to comply with regs, IWI literature states to use only U.S.-made magazines (they are one of the firearm’s three U.S.-made parts needed for compliance).

Each rifle digested 100 rounds after initial zeroing and no malfunctions were noted beyond the bad ammo already mentioned. The 7.62 NATO model really put a hurt on its brass during the extraction and ejection processes. It was not quite at the Heckler & Koch fluted-chamber damage level, but it was almost universally banged up to the point of being non-reloadable.

Rapid-deployment drills revealed that the ACE ergonomics and handling were top-notch.

While time and exposure to other firearms have dulled the romanticism of my youthful battle-rifle dreams, I fully appreciate any gun that performs its core tasks with total reliability. The Galil ACE is every bit a 21st-century redesign of a storied and battle-tested platform. Either of the ACEs I tested could fulfill the battle-rifle role with aplomb.

galil ace specifications

Check it out HERE

RELOADERS CORNER: Bullet Jump, Three

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In this final installment you’ll learn how to take bullet jump completely out of the equation, but it’s not just that simple… Here’s how to get the results you’re after. Keep reading…

Glen Zediker

There’s one more concept to consider to fully finish the topic of bullet seating depth, and it’s literally on the other end of the equation from discussions on bullet jump.

Last two articles were all about a combination of the evils of jumping bullets and also some ideas on reducing the ill effects, and hopefully to the point of zero measurable group size differences. I also mentioned that there are some bullets that just don’t tolerate jumping.

JLK 105 VLD
Bullets like this tend (a true Davis-drawn VLD) not to shoot well unless they start right on or very near the lands. I sho don’t know for certain, but I really think it has at least some to do with, for want of a better way to describe it, their leverage: it’s a lot of front end ahead of the first point of land diameter. These really long bullets don’t have to tip much to shift alignment relatively more.

For many (many many) years it’s been generally held that starting a bullet touching the lands is the easy ticket to better accuracy. That’s hard to disprove. It’s a tactic very commonly used by Benchrest and Long Range Rifle competitors, and savvy long-shot hunters. Now we’re talking about zero jump. Myself and many others have referred to this bullet seating tactic as “dead-length” seating. To be clear: it’s the cartridge overall length that has the bullet nosecone actually sitting flush against the lands (touching on whichever point along the nose that coincides with land diameter). Some literally take that a step farther and increase contact force such that the bullet is sticking into the lands one or more (sometimes several more) thousandths, actually being engraved by the lands prior to launch.

There are two ways to attain or approach dead-length. One is through careful measurement using something like a Hornady LNL Overall Length Gage. That tool should be paired with a bullet-length comparator, and Hornady has one of those too, as do others.

Measure enough bullets using a bullet-length comparator and you will find length differences in a box of most any brand. A comparator, as has been shown before in my articles (because it’s a very valuable tool to increase handloading precision), provides a more accurate means to measure bullet length. It’s a simple tool: the bullet nosecone fits into the opening on the gage, stopping at a point (determined by tool dimension) along the nosecone. Not all such gages coincide with land diameters because both comparators and land diameters vary from maker to maker. They are all “close” but perfect coincidence doesn’t really matter because a comparator will allow a reading at the same point of diameter regardless. Measuring from the base of a bullet to the bullet tip is inaccurate, and not nearly “good enough” to provide a precise enough measurement to venture into lands-on seating depth experiments. The reason measuring from base to tip isn’t good enough is because, especially in hollowpoint match-style bullets, there are relatively huge variations in the consistencies of the tips. I’ve measured easy 0.020 differences in a box of 100. Can’t make bank on that.

Using the combination of the gage that shows overall cartridge length that has the bullet touching the lands and the comparator to precisely record this length, it can then be reproduced via seating die adjustment.

Hornady LNL gage setHere’s a tool set shown many times in my books and articles this pair or something similar is necessary to negotiate this step in handloading. Check it out HERE and HERE at Midsouth.

If using this method, maintain whatever usual neck sizing dimensions are for your routine loads. There’s no need or benefit from lessening the case neck “tension” (which is the amount, in thousandths of inches, of the difference between resized case neck outside diameter and the resulting diameter after a bullet is seated). If that’s, say, 0.003 then keep it at 0.003.

There’s another, maybe better, method to follow if (and only if) you have a bolt-gun that’s to be fed one round at a time. By that I mean the rounds are not feeding up from a magazine but are being manually inserted into the chamber. That method is to reduce the case neck tension or grip to a level that the bullet is free enough to move within the case neck such that it seats itself when the round is chambered and the bullet makes contact with the lands. That’s awfully light in-neck resistance. It can’t be so light that the bullet falls into the case neck, but light enough that it can be scooted more deeply with little pressure. For a number it’s 0.001, minus, and half of that is workable if the case necks have been outside turned (so they are dead consistent in wall thicknesses and therefore will reliably “take” that little tension, meaning respond consistently to the sizing operation). Need a bushing-style sizing die to get that sort of control over the neck sizing dimension.

This method is often called “soft seating.” It’s, as said, very popular with competitive precision shooters. The bullet, keep in mind, isn’t just touching the lands, it’s actually engaging the lands to whichever degree or distance that resulted from overcoming the resistance from the case neck. If you feel anything more than slight resistance in chambering a round, that’s too much resistance. Chances are that any soft-seated bullet will stick in the barrel so extracting a loaded round will likely result in a big mess (elevate the barrel a little to keep the propellant from dumping into the action). Pushing the lodged bullet back out and looking at it carefully gives a good idea of how much resistance it’s overcoming. If the engraved area is much over 1/16-inch, increase the neck sizing bushing diameter to likewise loosen up the case neck. The amount of engraving has a whopping lot to do with the bullet jacket material (you’ll see more with a J4 than with a Sierra).

If you follow this method, then finish the die-seated bullets “out” 0.005-0.010 inches.

Redding sizing die bushing
It’s necessary to be able to fine-tune neck sizing dimension to experiment with soft-seating. A bushing-style sizing die is best. The bushing might also change for different brands or lots of brass if there are thicker or thinner neck walls. Clearly, outside neck turning is a step toward consistency in this sizing operation.

The reason this method can give the overall best results is because it’s accounting for teeny differences in bullet ogives and it also is adjusting itself for throat erosion. As gone on about in the last couple of articles, a barrel throat is lengthening with each round that passes through. What was touching the lands, or jumping 0.015, even one hundred rounds ago is no longer valid, and it’s totally corrupt five or six hundred rounds later. It’s no longer a precise setting, meaning a precise seating depth, and it has to be checked and reset as the barrel ages.

Again, this is not a casual experiment. The level of control and precision necessary to make it work safely and as expected is a step or three beyond what most reloaders are tooled up to deliver.

Will lands-on seating work for a semi-auto? Yes. But only with adequate bullet grip to retain the bullet firmly in the case neck, and that means the same tension that would be used with any other cartridge architecture, and that means a minimum of 0.003 inches difference between sized and seated outside case neck diameters. I do it often with my across-the-course High Power Rifle race guns. Clearly the “soft-seating” tactic is in no way wisely feasible in a semi-auto.

WARNING!
MOVING A BULLET OUT SO IT TOUCHES THE LANDS WILL (not can) INCREASE LOAD PRESSURE! Even going from 0.001 off to flush on will spike pressure. When the bullet is in full contact it’s acting like a plug. I strongly suggest backing off one full grain (1.0 grain) before firing a bullet touching the lands. Then follow my “rule”: work up 0.2-grains at a time but come off 0.5-grains at a time! If there’s ever any (any) pressure symptom noted, don’t just back of a tenth or two, that’s not enough, not considering all the other little variations and variables that combine to influence the behavior of the next several rounds you’ll fire.

THREE REASONS DEAD-LENGTH SEATING WORKS
ONE: Accounts for and overcomes any minor variations in bullet dimensions.
TWO: Minimizes bullet jacket disruption on entry.
THREE: Virtually eliminates misalignment between bullet and bore.

SIDE NOTE
If you’re one who, as many readers have suggested to me, has found that seating a bullet to touch the lands is the only way they get good groups, consider the above three reasons this seating method works and then interpret. If, and this is more common than we’d like to see, you’ve got a factory bolt-action rifle the chamber is likely to be overly generous in size or a tad amount non-concentric, or both. The case wall consistency and also sizing and seating tooling, or all three, might likewise be sub-par. In other words: lands-on seating is overcoming a few rifle issues, not, in itself, proving it’s the one-way ticket to great groups. Mostly, getting the bullet into the lands essentially straightens out alignment of the whole cartridge sitting in that (maybe) big chamber.

The information in this article is from Glen’s newest book, Top-Grade Ammo, available HERE at Midsouth. Also check HERE for more information about this and other publications from Zediker Publishing.

Optics Terms Defined: Magnification and Objective Lens

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When it comes to optics for firearms, the specific terms that people use to describe them can be confusing. Here’s what all that argot actually means…

optics array

by NRA Staff
SOURCE: NRAFamily

Magnification
The magnification, or power, of a riflescope is expressed as a number corresponding to the size of an object viewed at a specified distance through the scope, relative to its size as seen with the naked eye. Put another way, an object 100 yards distant viewed through a 10X scope will appear to be the same size as if it were viewed with the naked eye from 10 yards away. Different scope magnifications are used for specific shooting activities.

High-magnification riflescopes from 15X to 50X with objective lens diameters of 40-50mm or more with adjustable objective-lens systems are popular for various types of centerfire rifle competitions such as benchrest and F-Class.

Varmint shooters normally prefer a scope with magnification levels of 12X to 24X and adjustable objective lens diameters of 44-50mm for their precision work.

Long-range big-game hunting demands a scope with an adjustable objective lens system of approximately 40mm diameter with power levels up to 15X that enable the hunter to judge game and wind conditions at extreme distances.

At dawn, dusk or during poor light conditions, scopes with large objective lenses of 50mm and above that gather all existing light are preferable, with powers between 6X and 12X. Illuminated reticles are a popular option on these scopes.

Low-power scopes of 1.1X to 4X with a wide field of view and fixed objective are well-suited for hunting in woods or brush at close range.

For general-purpose hunting, most sportsmen are well served by a 3-9X-40mm variable scope with fixed objective, which is a good compromise between a wide field of view for close shots (at 3X) and added magnification (at 9X) for distant shots.

As magnification levels increase, the field of view decreases, which makes target acquisition increasingly difficult. Increasing magnification also magnifies movement, making the reticle appear less steady and thus hampering the ability of many shooters to hold their point of aim. These factors conspire to make most scopes over 8X very difficult to use without a solid rest. When shooting from a rest on a bench, a narrow field of view and high magnification are less of a problem.

Objective Lens
The objective lens is the light-gathering lens at the front of the scope. The larger the diameter of the objective lens, the more light will be admitted into the scope. This results in a larger exit pupil with a brighter image.

Most riflescopes have objective lens diameters from 32mm to 44mm. These provide a good balance between light-gathering capability, cost and image quality. Such riflescopes are relatively lightweight and easy to mount on most rifles. For many hunting applications, such riflescopes are an excellent choice.

For hunting at dusk, dawn or in very low light conditions, the increased light-gathering capability of a larger objective lens may be a better choice. For such conditions, most scope manufacturers offer models with 50mm to 56mm objective lenses. However, there is a penalty to be paid for th is increased performance in the form of substantially increased weight, higher cost and difficulty in mounting a scope with such a large objective.

Varmint hunters and some target shooters prefer riflescopes with large 50mm or greater objective lenses for a different reason. They want a higher-power scope of 12X or more with a clear, crisp, flat image with excellent contrast and an adjustable objective to remove parallax. The image quality reduces eyestrain and enables them to clearly see small targets at long ranges and to judge wind and mirage precisely. They also spend considerable time looking through the scope with the rifle held on a solid rest, so unsteadiness from high magnification and a narrow field of view is less important.

7 Things to Do Before Rifle Season

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Preparation is the key to virtually any successful venture, and deer hunting is no exception! Here are some valuable tips on how to best spend your time getting ready to go… Keep reading.

hunting trip
Image by Jim Bulger/Colorado Parks and Wildlife

by Steve Johnson, NRA Publications

Hunting season officially starts in September in most states…even earlier in others. Most states open with archery season and, as things progress and the rut draws nearer, they have a shorter season for folks who hunt with firearms. As a kid, firearm deer season in Nebraska was always the holy grail of hunting. We would get our rifles out and head to the range, usually on a cool October afternoon, staple a paper plate up on the 100-yard backstop and head back to the bench. Most of the guys I hunted with would take a shot or two, and if they hit the plate say, “meh, good enough,” then case their rifle back up and let the next guy shoot. Strictly speaking, you may only require a permit, rifle, ammo, and knife to go hunting, but there is more to it. A lot more.

ONE: First off: Boots
If you’ve never had a bad pair of boots, it can make it hard to appreciate a good pair. If you’ve only had good boots, you’re lucky or smart. Before you rush out and just buy a pair of “hunting boots” think about where you’ll be hunting and spend some time researching the correct boot for your environment. We grew up hunting in Sorel pack boots, which are great, as they’re waterproof and warm. If you go with a leather boot, Danner is worth a look, just make sure to protect them with the manufacturer’s recommended product for waterproofing.

TWO: Clothes
Both underwear and outer wear require thought beyond “what’s the coolest camo pattern”: Consider breathability, insulation properties (especially when wet), how well it layers, windproofing, etc. Will you be hunting in a tree stand-stationary and exposed-or still hunting, where you can find a warmer spot to sit? Think about where you’re hunting and which performance features will mean the most to you, then purchase accordingly. Check out companies like Icebreaker for out-of-this-world wool clothing. Synthetics have come a long way in the past 10 years, and one of the very best is Sitka.

THREE: Blades
There are a lot of good knives on the market, from the timeless Buck 119 to hunting knives that are bound to be classics like the KA-BAR Gamestalker. The one thing a knife needs to do is get sharp and hold an edge. Taking a dull knife into the field is dangerous. A sharp knife makes work quicker, easier and safer. Trying to cut tough materials, tendons, cartilage and hide with a dull and slippery knife is a good way to earn a trip to the emergency room. Keep your knife sharp. Sharpening a knife is a lost art, so take the time and learn how to sharpen your blade, get a good one and build a “relationship” with that piece of equipment. It will likely be one you can pass to a son or daughter along with your love of hunting.

Check out Midsouth offerings HERE

FOUR: Gather Intel
Trail cams have become a very important tool for the hunter, regardless of the species you hunt. They provide a lot of information about the type of critters passing through and their schedules. Trailcams can be found easily online. Spend some time researching features and talk to friends to get recommendations on the best camera for your hunting application.

Check out Midsouth offerings HERE

FIVE: Prepare Your Hunting Grounds
Prior to season, you’ll also want to head out for an afternoon and make sure your stands are in good repair, and that nothing has broken over the off-season. If you pull your stands after the season, this is the time to get them reinstalled. Cutting shooting lanes while branches still have foliage is not a bad idea either, as the foliage makes it easier to see all the little branches that might be missed if you cut a lane after the leaves have dropped.

SIX: Pack it Up
Make sure you’ve selected the correct pack for your hunt. There are many types of packs, frame packs, soft shell packs, hybrid packs…it’s almost limitless. The basic rule: “go in light, come out heavy.” This is the right idea. Take in only the essentials, and make sure and include spare batteries for any device that you will be using. Carrying a separate GPS is still a good idea, as cell phone battery life is normally very short when compared to a handheld GPS unit. Plus, there is a very good chance your cell phone GPS won’t work in a remote area. If you are hunting a large expanse of land on foot or horseback, it’s also wise to carry an old-fashioned paper map of the area, as paper maps are lightweight, and the batteries never go dead. At least one good flashlight is a must. LED flashlights have much longer battery life and generate more light with less energy. Basic firs- aid equipment is also a requirement. You’ll also want to make sure that you’ve got a back up knife, extra gloves and stocking cap so you can rotate them as they become sweaty or wet.

Check out Midsouth offerings HERE

SEVEN: Nom Nom Nom
Nothing will make you long to leave your tree stand like an empty stomach (not to mention how noisy it can get.) Some healthy, high-energy snacks are also a must. Nuts provide excellent energy and salt that you need to help replace minerals. Beef jerky is also an excellent, high protein, higher sodium snack that is very lightweight.

RELOADERS CORNER: Bullet Jump 2

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Tips that help take bullet jump out of the accuracy equation. Find out how!

leade
This is an aluminum staub cut with a chamber reamer. It’s easy to see the transition to the lands. The more smoothly a bullet enters the lands, the better it will shoot. When seating depth can’t be idealized, choosing a “gentle” bullet is the best defense against ill effects of jump.

Glen Zediker

Last time I shared some insight about bullet “jump,” and specifically with respect to the viability of setting up a “zero-jump” chamber/ammo combination.

To hit the highlights: Jump is the gap the bullet must traverse when it leaves the case neck to engage the lands or rifling. Generally, best (and better) accuracy comes with this gap is reduced to a minimum amount, or at the least reduced. Better is better.

To go farther into this topic, it’s worthwhile to move the bullet around, seating it more or less deeply (nearer or farther from the lands at rest) to maximize accuracy. Clearly, there’s a limit on cartridge overall length if the rounds have to fit into a magazine box so they can feed right. In NRA High Power Rifle competition, the AR15 pilots are specifically not allowed to have the rounds feed from the magazine in semi-auto mode; each round must be loaded into the chamber one at a time for the “slow-fire” segments, which includes the 600-yard event. That means competitive High Power shooters using AR-platform rifles are free to move the extra-long 80+ grain .224-caliber bullets out to near or on the lands when chambered. That doesn’t really matter but it explains the popular “Wylde” chamber we tend to use. It’s got a long enough throat to free more case volume and also provide a bigger “expansion chamber” for burning propellant gases, but it’s not as long as a NATO-spec so should perform better with bullets that do have to be loaded deeply in enough to fit the magazine box. Something like a Sierra 80gr or 82gr Berger won’t usually shoot worth a flip loaded to mag-length. That bullet, and others similar, are simply too dang long for a .223 Remington case. A huge amount of the bullet swallows up the case interior.

Sierra bullets compared.
It’s not all in the ogive specs, but it’s influenced by it, because those specs influence the overall profile of the bullet. Here’s a .224 Sierra 77gr MatchKing next to an 80gr MatchKing. The first is approximately 8 calibers, the 80 is approximately 12. The marks indicate the location of the first point of coincidence of land diameter. Considering the overall profile differences, it’s pretty clear that the 77 jumps with better results when each is loaded to the same cartridge overall length. There’s just 3grs difference in these bullets but they’re worlds apart in both tolerance and performance.

The best defense against ever worrying over jump, meaning whether you’re getting good accuracy regardless of the amount of bullet jump (well, at least within reason…) is bullet choice. Specifically, a tangent-profile bullet with a conservative ogive. Recollecting from some materials I did a while back, a “secant” profile is a sharper taper-in from bullet body to bullet tip; a tangent is a smoother transition. Secants, more or less, have a “shoulder” indicating a more abrupt taper rather than a smooth arc. For examples: true VLD (very low drag) and the Hornady A-Max are secant.

Bullets with relatively shorter nosecones and relatively longer bearing areas (length of the bullet that’s in contact with the rifling) are likewise more tolerant of jump.

Sierra 69, JLK 70 VLD
Here’s an example of different .224 bullet profiles at essentially the same weight. A Sierra 69gr MatchKing on left and a JLK 70gr VLD. The tangent 8-caliber-ogive (approximate) Sierra shoots great when it’s jumping; the secant 15-caliber-ogive VLD tends not to shoot well at all unless it starts touching the lands.

There’s been a trend for many years now toward creating bullets with higher ballistic coefficients. Worthwhile pursuit! Only issue is that when a bullet design features better aerodynamics, the features of that are, yep, longer nosecones with shallower angles. The ogive (what I’ve been more descriptively calling the nosecone because it’s easier to picture) usually is expressed in calibers. Technically it’s “calibers of ogive,” and that’s the ogive radius divided by the caliber. To me it’s easier to picture looking at the “other side” of the equation: the arc that scribes the profile in multiples of the bullet’s caliber. So, a 7- to 8-caliber ogive is a tighter circle (more rounded profile) than a 12- or 15-caliber ogive. Most of the “high-BC” profiles use a 15, some more. In other words, they’re stilettos.

calibers-of-ogive
Here’s an illustration of calibers-of-ogive from Sierra. That transition area from bullet diameter to first point of contact with the lands (which will be land diameter, and at least 0.005 smaller) has influence on how well a bullet endures jump. A lower-number is favorable in this regard. In this illustration the ogive radius, 2.240 inches, divided by the caliber, 0.308, gives 7.27. That should tolerate jump well.

I’m kind of breaking this down farther and faster than exercising good technical care in covering this topic should warrant, but: comparing both same-weight and same-caliber bullets, the longer it is the more sensitive it’s going to be to jump.

I have shot way too many high-X-count 300-yard cleans with bullets jumping 0.030+ inches to say that it’s not possible to have good accuracy unless jump is minimal. I admit that’s only a 1 moa group. I’m also using what some makers call a “length-tolerant” bullet, and specifically that’s a 77gr Sierra Matchking, and the same goes for a Nosler 77 or Hornady 75 HPBT (not A-Max). It’s the bullet form, not just its weight, that has the strongest influence on all this.

So, do you have to abandon better ballistics to attain better accuracy? Maybe. At least to a point. With the smaller calibers, which don’t have other advantages larger calibers have simply by virtue of weight and sectional density, there tends to be an effectively greater discrepancy between the lighter and heavier (again, it’s really shorter and longer) bullet ballistic performances.

A rifle with a generous-length magazine box provides greater jump-reduction via loaded round architecture. If there’s enough room, a bullet can be scooted out to the limit of the space within the box.

As always, well at least usually, there are tools! Get them and use them. A gage “set” from Hornady is well advised. There are others similar. I’ve been using their LNL Overall Length Gage and Bullet Comparator for many years and receive needed results. The first tool indicates the seating depth that touches the lands, and the second provides more reliable and accurate means to measure and record it.

Hornady LNL gage
This Hornady LNL gage pair gives you the tools needed to determine the jump you’re getting with the bullet you’re using. Check it out HERE

The leade, which, again, is the transition to the lands and determined by the chambering reamer (or throating reamer if custom-done) does influence tolerance for jump. The shallower the angle the better, but, that’s a two-edged issue. Take a commonly-used 3-degree leade and make it a more preferable 1.5-degree leade and that takes way on more than double the distance (length of cut) to attain. Again, when there’s a magazine getting in the way of bullet seating depth flexibility, a shallower leade eases transition into the barrel bore for a jumping bullet, but also increases jump. There are some cartridges, like David Tubb’s 6XC, that were designed specifically to “perfect” all these relationships: magazine-mandated cartridge overall length, bullet choice, and leade in, and it’s one reason it owns the records it does. Otherwise, it’s often a compromise… But don’t compromise accuracy for anything. A smaller group is, in the long run, the best defense against both wind and distance when it comes to hitting a target. Reliable feedback equals correct adjustments.

The preceding was adapted from Glen’s newest book, Top-Grade Ammo, available here at Midsouth. For more information on this book, and others, plus articles and information for download, visit ZedikerPublishing.com

FIREARMS: Five Good Reasons To Reconsider The Ruger Mini-14

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The AR15 platform is decidedly not the only way to go… Let’s revisit another American-made classic that might just win you over. Keep reading…

Mini-14s

 

by Brian Sheetz, American Rifleman

When it comes to .223 Rem. semi-automatic rifles, Ruger’s Mini-14 has long been one of the obvious choices (technically, the Mini-14 has the more desirable 5.56 NATO chamber, which allows use of surplus ammo). And it’s no wonder, considering it offers nearly the same handiness as the M1 Carbine, the ballistics of the AR15, and the feel of the classic M1 Garand and M14. The Mini’s popularity confirms its strong perceived relevance among a wide range of users, and sustained sales for more than 40 years is evidence of its sound design — even if it’s unfairly judged by the same criteria as today’s predominant platform, the AR, which enjoys the huge advantages of U.S. military adoption and unlimited manufacturing sources. So while some consider the Mini a bit dowdy or lowly, it is actually a serious standout worth giving a second look. Here are just five of the many reasons why a Mini-14 Ranch, Tactical, or Thirty model should be on your short list the next time you shop for a modern rifle:

One: The AR may not be right for you.
 As difficult as it may be for some to believe, not everyone finds the AR platform appealing. There are a number of reasons why, but two come quickly to mind. The first is that its appearance may be too “tactical” for some people’s tastes; aesthetics can be subjective. And the second is that its controls may not be intuitive for some users because of their physical makeup and/or lack of prior training. In contrast to the former, most versions of the Mini have a sporter-like profile and some feature wood stocks, making them right at home in saddle scabbards, pickup trucks and, more importantly, in the minds of many for whom the sight of a traditional rifle is less likely to arouse unwanted attention. As to the latter, the Mini’s centrally located safety, its hook-rock-and-lock magazine design, and its beefy, integral charging handle make for a straightforward manual of arms with the respective benefits of rapid employment, secure loading and positive chambering. Add to these factors the Mini’s light overall weight (6 lbs., 12 ozs.) and handiness (36.75-inch length), and you have a combination of qualities that is difficult to ignore.

Two: The latest Minis are more accurate.
The Mini has long suffered from a reputation among many users for poor accuracy. Theories abound as to why that is the case: My own is that the considerable mass of the operating slide impacts harshly against the gas block, which is bolted directly to the relatively thin barrel, not allowing the barrel to return to its precise point of rest between shots. But in 2005, Ruger retooled the Mini-14 production line and most shooters agree that, beginning with the 580-prefix series guns made since then, shooting 2-inch groups at 100 yds. is not out of the question. Again, it may come as a surprise to some, but not everyone needs a half-m.o.a.-capable rifle. Many tasks just don’t require that level of accuracy. In fact, most hunting and self-defense situations are in that category. Also, my experience is that accuracy and reliability in semi-automatic rifle actions is usually inversely proportional. So, anything that the Mini lacks in the way of accuracy is, practically speaking, likely more than made up for in reliability and cleanliness of operation and in lack of ammunition sensitivity.

Mini-14
Classic lines and ergonomics make the Ruger Mini-14 appeal to those who have had experience with more conventional rifles.

Three: The Mini is one of few semi-auto .223s available in stainless steel.
 For boaters, coastal dwellers, and others for whom corrosion is an issue, the Mini is one of the few factory semi-auto rifles available in stainless steel, which can greatly reduce the necessity for fastidious, immediate maintenance. Because of their simple fixed-gas-piston system and Garand-style rotating bolt with two large locking lugs, Minis are generally not maintenance-sensitive anyway, but when it comes to harsh environments, particularly, the advantages of keeping stainless steel free of corrosion are undeniable — especially when gun maintenance cannot be performed as regularly as it should. Note that, with the Mini, stainless construction means that the barrel, receiver, bolt, operating rod, trigger group, and many other small parts are stainless steel. Blued guns, of course, use chromemoly steels in many of those same large components, but even in those guns, many of the smaller components are made of stainless. The broader point, of course, is that the Mini is made largely of steel — not polymers or aluminum — and steel’s material properties lend it a durability and longevity that lighter-weight materials simply cannot match.

mini-14 stainless
A simple, well-proven design that’s even available in stainless steel makes the Mini-14 appeal to many who just haven’t warmed up to the AR-platform firearms.

Four: 20- and 30-round factory magazines are widely available and reasonably priced.
This had been a longstanding bugaboo that plagued the Mini-14’s reputation. Ruger has produced 20- and 30-round magazines since the gun’s earliest days, but, until just a few years ago, it sold the latter only through law enforcement channels. That spurred the production of a raft of inferior aftermarket magazines, which did nothing to bolster the Mini’s otherwise enviable reputation for reliability. Nowadays, factory-fresh, Ruger steel magazines — a durable design that has functioned virtually flawlessly since its inception — are available for sale in the usual commercial channels at reasonable prices. In addition, flush-fitting 5-round magazines are also available. All feature a projection on the follower that activates the gun’s bolt hold-open once the last round has been fired. (The hold-open can also be manually activated by way of a button atop the receiver rather easily.)

mini-14 magazines
A range of quality steel magazines is available from Ruger, and there are many others on the aftermarket. Ruger offers 20-, 30-, and 5-round (flush-fit) magazines. Shown are a 30 and a 5.

Five: It’s recently available in .300 Blackout.
This option should make an already proven platform even more appealing and versatile — especially for those who would like to hunt with a Mini in areas that require a caliber greater than that of the .223 Rem. Of course the Mini has been available in 7.62×39 mm for years as the Mini Thirty, albeit limited to 20-round factory magazines, but the new .300 Blackout Mini brings .30-cal. presence to the familiar platform with the advantage of feeding from the same .223-cal. 20- and 30-round magazines. Ruger is selling the gun with a magazine marked “300 AAC Blackout” simply as a precaution, but there is reportedly no difference mechanically between it and the .223 magazine. It makes one wonder if the smart move might be to buy two Minis, a .223 Rem. and a .300 Blackout, along with a raft of magazines to fit either interchangeably as a practical, powerful hedge against bad times.

Check out the Minis HERE

SKILLS: Problems (Some) Riflescopes (Can) Have

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The more you know the better choices you can make. Consider all of this carefully before you purchase your next riflescope.

by NRA Staff

There are some problems that riflescopes can experience, but you should note that modern manufacturing techniques can make a real difference. There are three main issues:

Parallax
Many riflescopes suffer from a condition that stems from the inability of a scope to remain focused at all ranges. The compromise solution for most scopes is to design them to focus at infinity or one specific range. This serves most purposes and simplifies scope design. When a scope is properly focused at the chosen zero range, parallax will be minimal.

However, this is not acceptable for some applications, such as varmint shooting and hunting at long ranges. Under such conditions, parallax becomes a problem that must be addressed. Scope makers solve this problem by offering models with adjustable objective (AO) lenses. AO models incorporate adjustable objective bell housings with graduations marked on the traveling edge that allow quick and easy adjustment to remove parallax at any range. Alternately, some models locate the parallax adjustment in a third turret on the main tube for more convenience. Although AO and side-focus models cost more, shooters demanding enhanced accuracy often feel they are worth the asking price.

Sealing
Most quality scopes are sealed. This means the outer lenses and adjustment systems must be sealed against ingress of water, dust and dirt. This is very important, as dust or dirt inside the tube will degrade the image in several ways, mainly by appearing as black spots within the field of view. Dirt inside the tube can also jam the delicate adjustment system. Moisture inside the tube can cause fogging so that the shooter cannot see through it. Moisture can also cause corrosion of inner parts and surfaces.

Scopes are sealed at the factory by first attaching them to a vacuum pump that removes all air from inside the tube. The tube is then filled with dry nitrogen gas to prevent fogging and then subsequently sealed. Of course, if you remove a turret or the ocular bell housing, the nitrogen gas may escape, thus compromising your scope’s anti-fogging capability.

Many high-quality scopes have double seals to ensure gas-tight integrity. However, no scope is permanently waterproof despite advertising claims to the contrary. Wear, tear, impacts and age all conspire against the tube holding the nitrogen gas. For this reason, most scope manufacturers will reseal and refill a scope at modest cost.

Want to check your scope for leaks? Try this simple test: Fill a sink or washbasin with warm water. Immerse your scope in the water for five minutes and check for bubbles coming from the tube. Bubbles mean leakage and such scopes should be sent back to the manufacturer for resealing and refilling.

Shock & Recoil
Newtonian physics are not kind to riflescopes. In addition to maintaining their accuracy, reliability, and water-tight integrity, scopes must withstand the considerable shock of repeated recoil many times the force of gravity. The delicate adjustment mechanisms and lens mounts are particularly susceptible to high G loads and must be designed accordingly. Scope makers are well aware of this and have designed shock resistance into their products. They have been so successful that shock resistance is now taken for granted by shooters and manufacturers alike.

Air rifles are a special case. Be careful when using conventional riflescopes on a spring-piston air rifle. If you do, the lenses may come loose, sometimes within a few shots, and your scope could be damaged or ruined. The reason is that spring-piston air rifles recoil in both rearward and then forward directions while a conventional rifle recoils only rearward. Thus, a riflescope for a conventional firearm need resist G forces in only one direction — rearward. Air rifle scopes must resist G forces in both directions. This requires a special scope designed for the purpose.

RELOADERS CORNER: Bullet Jump: does it really matter? (Part One)

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The distance a bullet travels to enter the lands is a topic of much concern to the precision shooter. This series takes a look at why it matters, and also when it doesn’t…

Glen Zediker

bullet jump
Here’s jump: it’s the distance from the end of the case neck portion of the chamber to the first point the bullet will engage the lands or rifling.

Bullet jump: the open space a bullet must span until its first point of sufficient diameter engages the barrel lands.

Last week I had a long phone conversation with a fellow who had been bitten by two bugs, two somewhat conflicting bugs (at least seemingly so on the onset). The one was a regrouping equipment project for USPSA-style practical rifle competition, and the other was for a desire to maximize accuracy, which is to minimize group size. This fellow had been involved in competition long enough to decide to stay with it, and was re-upping his AR15 upper with a new custom barrel. He wanted to have the best accuracy he could buy, and that’s a worthwhile pursuit as long as there’s a budget that supports it.

The subject of bullet jump became the dominant topic.

Yep, he had read my books and a few others and developed the impression that minimizing bullet jump was one crucial component to maximizing accuracy. That’s fair enough. I’ve gone on about it, as have others. Adjusting bullet seating depth can make a big, big difference in shot impact proximities. However! The reason bullet jump matters — usually — is largely, almost exclusively, because of some bullet profiles being more finicky than others. Namely the longer and spikier “very-low-drag” type bullet profiles.

The first point of “major diameter” on a bullet is what coincides with the land diameter in the barrel. If that’s a .22 caliber with 0.219 diameter lands, then the first point along the nosecone of a bullet that’s 0.219 is the distance. Gages that measure this distance (Hornady LNL for instance) aren’t necessarily going to provide perfect coincidence with land diameter, but still provide an accurate bullet seating depth that touches the lands.

If you find the cartridge overall length, which really means bullet seating depth, that touches the lands (coincides with land diameter) then subtract that from what you then measure when the bullet is seated deeply enough to fit into a magazine box, that right there is the amount of jump.

Hornady LNL gage
There are other ways to find it, but the Hornady LNL Overall Length Gage makes it easy. I’d be lost without this tool. Use it to determine the current distance to engage the lands for any bullet you’ll use (it works also as a way to monitor throat erosion). Get one HERE

Dealing with an AR15, or any other magazine-fed rifle, assuming we are wanting the rounds to feed from the magazine, is that there’s a finite cartridge overall length that will fit into the magazine. So. We’re almost always going to be dealing with some amount of jump, unless one or two things can be manipulated to reduce or eliminate it.

AR15 loaded magazine
A box magazine sets the effective limit on overall cartridge length. Getting a bullet to sit close to the lands when the round is chambered requires either some trickery in chambering specs or, mostly, bullet selection. However, with selection there is also limitation. For safety’s sake, no factory loaded round is going to approach lands-on seating structure. When a bullet touches the lands at rest, pressures will, not can, spike. All good, if it’s accounted for. This sort of “fine-tuning” is strictly a (careful and knowledgeable) handloader’s realm.

The one is that the influence of rifle chamber specs with respect to either more or less jump is pretty much exclusively in the leade or throat. That’s the space that defines the transition from end of the chamber case neck area to entry into the lands. The closer the lands are to the chamber neck area the shorter the jump will be with any bullet. That is the leading difference between a SAAMI-spec .223 Remington chamber and a 5.56 NATO chamber. The NATO has a much longer throat. I’ve written on that one a few times…

A shorter throat has goods and bads. The main good is that, indeed, any and all bullets are going to be closer to the lands in a round loaded to magazine-length.

But the “two” in the things that influence jump is bullet selection. It is possible to find a combination that will easily have the bullet sitting right on or very near the lands at the get-go. That’s going to be a short, and light, tangent ogive bullet within a SAAMI-spec .223 Remington chamber, or (and this is what I have done) a barrel chamber finished using a throating reamer to get even closer. In general: the nearer the first point of major bullet diameter (remember, that’s the land diameter) is to the bullet tip, the shorter the jump will be, and that’s because this point is “higher.”

Hornady 52gr HPBT
Looking through a good factory loading manual down amongst the “lighter bullet” selections, take a notice of the overall round length used in the test ammo. Magazine box maximum for an AR15 is 2.25 inches (it’s actually 2.26 at a maximum, but don’t cut it too close). If you see a length less than that, then there’s a bullet that can be seated on or near the lands at magazine length. Simple.
Here’s a great example that I can tell you absolutely will engage the lands in an AR15 loaded to magazine length. As a matter of fact it will be over 0.020 into the lands at magazine length, so certainly must be loaded to an overall length well less than that… It also shoots little groups. Check it out HERE

Throat erosion is going to lengthen the throat. Can’t stop that. The cartridge structure that was jumping, say, 0.005 on a new barrel is jumping more than that after literally every round fired through it. After some hundreds of rounds it’s jumping a few multiples of 0.005. (How much or how many is not possible to forecast because way too many factors influence the amount and rate of throat erosion. Just have to keep checking with the gage I suggest you purchase.) This is the reason I specify a custom dimension to get reduced jump: with the right hands using a throating reamer it’s easily possible to maintain land contact at magazine length seating even after a lot of rounds have gone through. Bullets will begin being seated more deeply and then get nudged out as the throat erodes.

So, where the conversation ended was this: If (and only if) someone is willing to take the time and make the effort to carefully establish and then control a reduced or eliminated amount of magazine-loaded jump then, yes, it’s a fine idea! It’s also an idea that likely will result in the best accuracy. I’ve done it in one of my AR15 match rifles, and it’s the best shooting I’ve ever owned. The hitch is that the rifle becomes what I call a “one-trick pony.” It’s not always going to accept bullets and loaded round architectures that stray from the carefully calculated dimensions originally set down. It’s also not likely going to perform safely with every factory-loaded round out there, and you can forget (totally forget) ever firing a NATO-spec round.

There’s a whopping lot more to this whole topic, and we’ll look at the other end of the spectrum next time.

The reason that reduced amounts of bullet jump increase accuracy, in a perhaps overly simple but entirely correct way to understand it, is because there’s simply less potential for disruptive entry into and lands and then through the bore. There’s less misalignment opportunity, less jacket integrity disruption opportunity. There is a lot more that can be discussed in finer points, of course…

The preceding was adapted from Glen’s newest book, Top-Grade Ammo, available here at Midsouth. For more information on this book, and others, plus articles and information for download, visit ZedikerPublishing.com