Category Archives: Reloading

Everything from case prep, to components, the reloading category will be home to articles about reloading and reloading items.

Case Sizing 1: Sizing Die Selection

Facebooktwittergoogle_pluspinterestyoutube

 

The following is a specially-adapted excerpt from the forthcoming book,” Top-Grade Ammo,” by author Glen Zediker, owner of Zediker Publishing. Click here to order.

by Glen Zediker

Most discussions about reloading tend to center around tools, and the cartridge case–sizing die used to refurbish a spent case is one of the most important. Last time, we were left with a case that had been expanded to the limits of the chamber, plus maybe just a little. The sizing die gets it back in shape for a reuse.

First, I only advise the use of a full-length sizing die for bolt guns or semi-autos. As suggested, a full-length die contacts the full length of the case, the full diameter, from case mouth to case head, and can also contact the shoulder area. There are neck-only dies that, as suggested, only resize the case neck so it will hold another bullet. They don’t touch the case body, and many don’t contact the case shoulder.

As far as brands go, I’m partial to Forster. I like the expander design. It’s located high, so there’s more support about the case when the neck is withdrawn back over it. I still polish this appliance, and recommend always doing so if it’s possible.
As far as brands go, I’m partial to Forster. I like the expander design. It’s located high, so there’s more support about the case when the neck is withdrawn back over it. I still polish this appliance, and recommend always doing so if it’s possible.

A full-length sizer will compress the case body down to the die interior dimensions, which are close to those of factory new ammo. Keep in mind that we’re talking about scant thousandths of inches, but those add up.

Whether it’s a bolt-action, lever-action, semi-automatic, a rifle has to function, and ensuring that cartridges feed into and out of the chamber is the clearly most critical functioning necessity.

If you’re big into or only into single-shots, neck-only sizing is possible, certainly. But even then there’s honestly little to no accuracy or performance benefit from it. The idea is that maintaining the case-body dimensions that more closely replicate the rifle chamber generally tightens up everything and produces better accuracy. Makes sense. But unless we’re working with measurably perfected brass and perfectly concentric rounds and seating bullets to touch the lands or rifling, none of those attributes matter a whit. Any rifle with an ejector is going to warp case bodies, for instance, so the dream of case-to-chamber harmony just can’t exist.

This is a Redding Type-S conventional full-length sizing die. On these, the die interior is pretty much the same as the rifle chamber interior, just a little smaller.
This is a Redding Type-S conventional full-length sizing die. On these, the die interior is pretty much the same as the rifle chamber interior, just a little smaller.

If neck-only sizing was all that influential, then new cases wouldn’t shoot the good groups that they will.

Another thing a full-length sizing die does, or can do, is contact the case shoulder. This is critically important in sizing for repeating rifles.

Last time we talked about what happens to a cartridge case during firing, and it’s not pretty. One of the things that happens is that the case shoulder gets blown forward, which means that if the case were standing up on the bench, that the shoulder will be higher (taller) than it was before firing. To ensure function, and safe function, that dimension needs to be corralled and brought back to what it should be.

To polish the expander, chuck the stem (lightly) in a drill and use a wrap of masking tape to cushion the threads. I first run the edges of the expander over a hard stone to break them and smooth them over, but I don’t run the stone against the body of the expander. Then run it over wet 600-grit emery paper. I use emery paper available at many auto-parts stores. Aluminum-oxide lapping compound works well also. There should be no measurable reduction in the expander body diameter after using the 600-grit paper, but if there is, it’s not going to amount to anything that can have a harmful effect.
To polish the expander, chuck the stem (lightly) in a drill and use a wrap of masking tape to cushion the threads. I first run the edges of the expander over a hard stone to break them and smooth them over, but I don’t run the stone against the body of the expander. Then run it over wet 600-grit emery paper. I use emery paper available at many auto-parts stores. Aluminum-oxide lapping compound works well also. There should be no measurable reduction in the expander body diameter after using the 600-grit paper, but if there is, it’s not going to amount to anything that can have a harmful effect.

There are full-length sizing dies with interchangeable bushings that size the case neck. The idea is to control the amount of case neck reduction, and it also allows the use of a sizing die without an inside-neck sizing appliance (usually called an expander). Good idea. Still, I don’t recommend this style of die for most shooters. One reason why is that there’s a small amount of case neck that doesn’t get sized. Over time, this can create or increase the “case neck donut,” the small raised-up ring of brass that exists inside the case at the case-neck/ case-shoulder juncture. But the die is not the sole cause. Suffice it to say, the additional and inconsistent additional constriction against the bullet isn’t a good thing.

I also do not advocate running a sizing die without an expander or sizing button to control the case neck inside diameter (i.d.). That’s another touted advantage of the bushing dies. That only works well if case necks are perfectly uniform in thickness. Otherwise, it creates off-center case mouths, and ultimately, inconsistency, in bullet pull.

Neck-bushing-style dies (in conjunction with full-length sizing die body) seem like a really good idea, and they can be — but they are another step in controlling case dimensions that most of us don’t want to take or need to take. My biggest issue with bushing dies is that they don’t size the full length of the case neck, and that can create problems. The arrow points to the small area of the case neck that is sized.
Neck-bushing-style dies (in conjunction with full-length sizing die body) seem like a really good idea, and they can be — but they are another step in controlling case dimensions that most of us don’t want to take or need to take. My biggest issue with bushing dies is that they don’t size the full length of the case neck, and that can create problems. The arrow points to the small area of the case neck that is sized.

One of the reasons that the neck-bushing dies came about was from the warranted complaints that conventional sizing dies sized down the case neck outside too much. Most do. Then the expander or sizing button has to open it back up that much more. That’s a lot of stress on the case and the reason for polishing the expander. Another easy fix is to have a machinist open up the neck area in the die. That’s a good idea. I can’t get after the factory techs too much in setting the specs for their dies because they’re trying to cover their bases on all the potential combinations out there, but that doesn’t mean we can’t improve it. There doesn’t have to be more than 0.005 difference between outside diameters and inside diameters to ensure fully adequate sizing. In other words, if the case O.D. is sized down to 0.005 smaller than the measured O.D. after the expander has passed back through, that’s plenty. Check your die by sizing a case without the expander in place. Less is better, but don’t cut it too close; keep room to account for different brass brands, which have different wall thicknesses. This trick will help maintain more material consistency over the life of a case. Otherwise, it’s like bending a piece of metal back and forth until it breaks; the same effect does influence case life when there’s excessive material movement.

One of the best ideas in sizing dies is incorporating a neck-shoulder bushing. These work well because they allow for control over dimensions, including case-shoulder compression, and without the criticisms made against neck bushings. This is a set from Superior Shooting Systems LLC. It’s for 6XC but can also be used, with an appropriate bushing, for .308 Win. Full-length dies with neck/shoulder bushings can control the neck diameter and still get the full neck cylinder sized.
One of the best ideas in sizing dies is incorporating a neck-shoulder bushing. These work well because they allow for control over dimensions, including case-shoulder compression, and without the criticisms made against neck bushings. This is a set from Superior Shooting Systems LLC. It’s for 6XC but can also be used, with an appropriate bushing, for .308 Win. Full-length dies with neck/shoulder bushings can control the neck diameter and still get the full neck cylinder sized.

A small-base full-length sizing die is an option in some die makers’ catalogs. As implied, this reduces the lower portion of the case a tad amount more. I’ve never encountered the need for one in an AR-15. Most have fairly generous chambers, especially if it’s a true NATO-spec. However, I always use one in my M1As, especially when working with a tough case, like a Lake City, that has to fit back into a relatively undersized match chamber. One of the best I’ve used is from Dillon (just the standard die that comes on the Blue machines); Redding also makes a “National Match” sizer engineered just for that rifle.

Next time, I’ll go step-by-step on how to set up a sizing die.

Get looking around this website and locate a cartridge headspace gage, and get it bought. I’ll show you how to use it next time. Either the Hornady LNL Cartridge Headspace Gage or the Forster Datum Dial (shown here) is my recommendation. They both work well. There are also drop-in style gages that will suffice to keep your ammo safe, but won’t give a number to work from.
Get looking around this website and locate a cartridge headspace gage, and get it bought. I’ll show you how to use it next time. Either the Hornady LNL Cartridge Headspace Gage or the Forster Datum Dial (shown here) is my recommendation. They both work well. There are also drop-in style gages that will suffice to keep your ammo safe, but won’t give a number to work from.

 

 

 

 

 

 

 

 

 

 

Custom Products

17217 Brookhouser Rd.

Saegertown PA 16433

814-763-2769

 

Superior Shooting Systems LLC

800 N. 2nd St.

Canadian TX 79014

806-323-9488

 

HODGDON’S RIFLE-CARTRIDGE LOADING HELP

Facebooktwittergoogle_pluspinterestyoutube

As we’ve previously noted, Midsouth Shooters Supply customers enjoy using Hodgdon powders, in part because the company makes great products, but also because the company’s experts supply plenty of help for shooters who want to get started in reloading.

We previously noted here that some of the company’s available materials appear in the Hodgdon Reloading Education section. Click here to see the landing page on which Hodgdon begins the education process. Click here to see Safety precautions. Then click the Reloading for Beginners tab to get an overview of the basics of handloading. This time, we want to probe more deeply into the data available for reloading rifle cartridges.

The Hodgdon Rifle Reloading Data page gets you started by asking you to select a cartridge from a pulldown menu. The lineup of available cartridges begins at the 17 Ackley Hornet and continues through the 50 Browning Machine Gun, or 50 BMG. What’s nice is there are dozens choices of currently available commercial favorites, such as the 30-06 Springfield, as well as popular wildcats (219 Wasp), new entries, such as the 28 Nosler, and proprietary rounds, such as the 240 Weatherby Magnum and others.

The Hodgdon Rifle Reloading Data page displays a pulldown menu with a lineup of available cartridges from 17 Ackley Hornet through 50 BMG. Magnum and others. Step 2 is selecting a bullet weight, then a powder manufacturer, then a specific powder.
The Hodgdon Rifle Reloading Data page displays a pulldown menu with a lineup of available cartridges from 17 Ackley Hornet through 50 BMG. Magnum and others. Step 2 is selecting a bullet weight, then a powder manufacturer, then a specific powder.

Once you’ve selected a cartridge, which for our purposes here is the 25-06 Remington, you’re then able to select a range of bullet weights. In the case of the 25-06, that ranges from weights from 75 to 120 grains and a variety of bullet profiles.

When you select a bullet weight (or weights), the site returns a range of data for that load. Our search was to “select all,” which provided load data beginning with the 75-grain Hornady V-Max bullet. We then expanded that window and saw additional information about that choice, including Case: Remington, barrel twist (1:10”), primer (Remington 9 1/2, Large Rifle), barrel length (24 inches), and trim length for the case (2.484 inches).

Then, in more detail, the window for the 75-grain Hornady V-Max load lists the recommended powders, starting loads, and maximum loads, along with estimated pressure outcomes. The lowest-pressure starting load for the 25-06 75-grain Hornady V-Max round was with 58.0 grains of Hodgdon H1000, which will produce a velocity of 3,135 fps and develop 35,300 copper units of pressure (CUP).

The highest-pressure choice for the 25-06 75-grain Hornady V-Max round came with IMR 4451 (58.5 grains), which will produce 3,781 fps and 60,300 PSI (not CUP in this case).

Of course, you can deselect various elements to narrow your search. One particular bolt gun we have chambered in 25-06 Rem. has proven it can shoot commercial 115-grain Winchester Ballistic Tip ammunition (SBST2506) into three-quarters-inch groups if the shooter does his part, and its downrange performance with a 200-yard zero gives a bullet drop of -6.0 inches at 300 yards, so we can hold top of deer — but still on the target — and expect a center hit at 300 yards.

Unfortunately, that specific bullet isn’t available in the Hodgdon tables, but the data are still useful in building a test load to create something like it. We could select a similar bullet weight, such as the 117-grain Hornady SPBT, then look at which powders we wanted to work with to get the commercial round’s stated 3,060 fps muzzle velocity. (There are other considerations besides velocity of course, such as the bullets’ different ballistic coefficients, but first things first.) Or we could buy another 115-grain bullet, such as the Nosler Ballistic Tip, then use the 117-grain powder recommendations to begin working up profiles to build our own home-brew commercial load.

We’d choose one whose maximum load had a little velocity headroom in it — such as the Hodgdon Hybrid 100V that produces 3,111 fps with a maximum load of 50.5 grains and not the highest pressure. In this case, that’s 50,400 CUP. But there are plenty of other choices if that recipe doesn’t produce the results we wanted.

Also, you can narrow your selections by manufacturer or specific powder if you have already have pet loads you like to work with.

And that’s really the value of the Hodgdon rifle-cartridge reloading table: You’re able to select proven, safe, and varied mixtures of bullet weights and powder to begin making your own tack-driver loads.

How We Work with Local Customers

Facebooktwittergoogle_pluspinterestyoutube

Midsouth’s not your traditional retailer. If you go back and look at our history, we’ve always been the same thing. We’re all about reloading, and mostly a mail order catalog since New Market, Tennessee back in 1969. With the advent of the internet, we grew into the retailer you know and love today. Click Here for more info on Midsouth History.

Welcome to Midsouth Shooters Supply
Welcome to Midsouth Shooters Supply

With that in mind, we started a new side of our business to better accommodate the growing interest from local customers to allow them a place to pick up their orders placed online, over the phone, or to stop in and place an order there at the counter. Thus, the pickup room was born, and with it a whole new phase of Midsouth came to be.

The Pickup Counter where you can place or pickup your orders
The Pickup Counter where you can place or pickup your orders
a sneak peak into our warehouse
a sneak peak into our warehouse

Using our pickup room helps local customers to save time, and money on shipping and hazardous fees. Furthermore, you have our friendly staff there to ask any questions you may have on reloading items, ammo, or upcoming seminars and reloading classes. That being said, check out the video below with some best practices when it comes to placing your order:

Now more than ever, we’re ready to serve our local customers. The next time you’re cruising down Interstate 24, stop in and pick up some powder and primers, avoid that hazmat fee, and experience our friendly customer service for yourself. We’re here Monday – Friday, 8:00 AM till 5:30 PM. We hope to see you soon!

Shop - Pickup - Save!

Reloaders Corner: The Cartridge Case

Facebooktwittergoogle_pluspinterestyoutube

The following is a specially-adapted excerpt from the forthcoming book,” Top-Grade Ammo,” by author Glen Zediker, owner of Zediker Publishing. Click here to order.

Bear with me! We’ll get started on the process of handloading next time when I talk about setting up a sizing die. But before that, it’s good to keep in mind what we’re dealing with, and that is a cartridge case, and also what happens to it during firing, which is what we’re setting out to remedy when we reuse it.

Rifle cartridge cases are made of brass, well, the reusable cases are (they can and have been made from steel and aluminum). There are no brass mines; brass is an alloy composed of copper and zinc and sometimes tiny amounts of other metals, like lead. The mix is usually about 70/30 copper to zinc. Different manufacturers use a different mix or blend, and that influences the nature of the material, and more about that shortly.

When a round is fired, here’s what happens.

When the firing pin or striker point contacts the primer, the cartridge is driven forward into the rifle chamber (as far as it is able to go).

When the primer detonates and its flame enters the cartridge-case flash hole to ignite the propellant, gases are produced that begin to expand the case.

As the propellant is consumed, gas pressure increases, the case head is driven backward against the bolt face, and the case neck and case shoulder are pushed forward as the case neck expands to release the bullet. The case essentially swells up like a balloon to fit the chamber, to the limits of the chamber, and this expansion is in all directions. So the back of the case is pushed into the bolt face and the front area is pushed or blown forward, while, during this, the case body is sealing (essentially sticking to) the chamber walls.

A cartridge case begins to contract just about immediately after it expands. The firing process takes scant milliseconds. Brass is both elastic and plastic. “Elastic” means it will stretch and contract. “Plastic” means it will stretch and stay. The elastic quality makes it expand and seal the chamber and then shrink back enough to be removed or extracted from the chamber. Plastic qualities mean it will also have sustained permanent change. Well, some of it isn’t really permanent because it can be changed again using tools, but some changes are permanent, whether they are literally smoothed over or not. Some cases tend to be harder — less plastic and less elastic — and that is almost always good, or so I say. It’s easy to see that since brass used in a semi-auto has to deal with at least some premature bolt unlocking, a harder composition is less “sticky” in extraction. Even for a bolt-gun, though, harder alloy tends to be smoother cycling. In a semi-auto, case life is strongly influenced by brass composition, and the harder the longer.

Thinking about what happened to the case, what it went through, during firing means we can anticipate the results and effects of dimensional changes. The areas of the chamber that have the greatest dimensional difference between those and the loaded round will have the greatest influence on the dimensions of the spent or fired case. Specifically, the spent case neck will now be too oversized to hold a bullet in place. The case shoulder will have lengthened (elevated if we’re standing the case on its bottom). The case body will have gotten larger in diameter. The case will also have lengthened overall (more about this in another article). What else? Some case material will have moved forward (brass flows in firing) toward the case neck. This material will have come from the area around the case head. The primer pocket will be larger in diameter.

Each firing, brass gets harder overall. In the areas where it expands the most, it gets even harder as it is “worked” through expanding and then being contracted. The tools we use to restore dimensions, the sizing die for good instance, create the contraction. And as suggested, the wall area near the case head gets thinner and the case neck walls get thicker.

All this means quite a bit to the handloader. First, get a clear picture of what’s happened to the spent cartridge case. Essentially, it’s expanded to more closely match the chamber dimensions. Of course, that means different spent-case dimensions from different chambers. Likewise, not all brass cases expand, or stay expanded, in the same way.

Case capacity, by the way, isn’t always as important as it might seem. Greater volume does mean more room for propellant, and expanding gases. With faster to medium propellants, it’s a “trade,” in a way of looking at it. A little less propellant in a little smaller capacity case nets about the same as a little more propellant in a little larger capacity case. Pressure and velocity will be about the same, either way. Now, in larger cartridges, and also often with double-base propellants in any size cartridge, more internal volume will very often mean more velocity at suitable pressure. Point is, don’t worry too much about more or less case capacity in .223 Rem. or .308 Win. I think the alloy composition is more important.

Now we can get started on patching them back up for another use…

Learn How to Keep Loading During a Powder Shortage (as best you can)

Facebooktwittergoogle_pluspinterestyoutube

It sometimes seems like the powder crisis will never end. As a retailer, we feel your frustration on a whole different level. We feel bad that we can’t get you the items you need. We feel worse that we don’t have the items available to sell. We feel even worse that our excuse is simply, “We don’t have it, and we haven’t gotten word as to when it will come in.”

It’s critical for any reloader to follow their recipe to develop an accurate load that works for them 99.99999% of the time, especially for distance or competition shooters. For those of us that bulk load for fun and frugality, the MOA accuracy isn’t as crucial, but by the very nature of reloading, we tend to develop more consistent ammo than what a factory can provide. Beyond that, reloading is exciting! You are working with a products that require care when handling, to create a piece of ammunition that can be used to train your skills, destroy varmints, or put food on the table. That’s incredibly satisfying, and warrants the attention to details that reloading deserves beyond most hobbies.

If this powder crisis has taught us anything, it’s how to develop a new recipe for our existing loads. As a community, we never shy away from doing research, keeping records, and paying special attention to detail. That being said, you don’t want to have to delve into your stacks of reloading manuals every time you want to load the same cartridge you’ve been loading for years. With the advent of Hodgdon’s newly revamped load data center, that process has become much easier. With just a few clicks, you can search for a powder that will replace your current powder, and check it’s availability at Midsouth Shooters Supply.

Hodgdon Reloading Data Center

Let’s say, for example, you’re loading 300 AAC Blackout because factory ammo is expensive, and a little hard to come by at times. You’ve been using H110 for over a year, but it’s constantly out of stock. Thanks for the fine folks at Hodgdon, you have new options at your fingertips.

Choose the load type

So, you just bought the Federal American Eagle 300 Blackout New Primed Brass, and a box of the Nosler 30 Caliber Custom Competition 220 Grain Hollow Point Bullets for a nice subsonic load, but you’re out of powder. According to Hodgdon, you can start using Lil’ Gun, a trusted powder that’s been used for years. That’s not your only option, but with the supply chain constantly being limited, it’s great to have any option.

Choose the Powder that will work with your cartridge, then check if it's in stock at Midsouth Shooters

Once you press “Get Data” you’re off to the races. Below, you can see that your options for starting, and maximum loads populate, as well as recommended primers, rifle specs for use, and other helpful pieces of information.

Load-Data-Loads

Using the data center, and cross-referencing Midsouth Shooters Supply’s In-Stock powder listing, you can get back to loading as soon as we deliver your powder, which we try to do as quickly as possible. Midsouth also has one of the lowest hazard fees around, but that’s a whole different article.

In-Stock-Smokeless-Powder

Have you used the data center to work up a new load due to powder unavailability? Have you noticed more of your favorite powders coming into stock lately?

SIG Sauer Introduces Elite Revolver Loads in 38 Special, 44 S&W Special and 45 Colt

Facebooktwittergoogle_pluspinterestyoutube

 

SIG Sauer Elite Performance Ammunition 125-grain 38 Special
SIG Sauer Elite Performance Ammunition 125-grain 38 Special

 

SIG Sauer Elite Performance Ammunition 230-grain 45 Colt
SIG Sauer Elite Performance Ammunition 230-grain 45 Colt

SIG Sauer Ammunition has introduced its first personal defense revolver cartridges, with loads in 38 Special, 44 S&W Special, and 45 Colt.

“With the recent proliferation of small-frame revolvers for personal defense, the demand for ammunition in these calibers is growing significantly,” said Dan Powers, president of the SIG Sauer Ammunition Division.  “SIG Sauer continues to expand caliber offerings for handgun shooters, which now includes the revolver market, and there will be introductions of additional revolver calibers in the coming weeks.”

All three cartridges are available in the SIG V-Crown jacketed hollow point (JHP) round of Elite Performance Ammunition in the following bullet weights:

— 125-grain 38 Special with a muzzle of velocity of 900 fps;

— 240-grain 44 S&W Special with a muzzle velocity of 800 fps; and

— 230-grain 45 Colt with a muzzle velocity of 950 fps.

Bullets are SIG Sauer’s proprietary V-Crown stacked hollow point. Ducta–Bright 7A coated brass cases provide enhanced lubricity and corrosion resistance.

The 38 Special is also available in SIG FMJ full-metal-jacket loads. Designed specifically for practice and competition shooting, these premium target rounds feature solid brass cases and copper-jacketed bullets that remain intact on impact. Clean-burning powders are used to reduce barrel fouling.

Click here to see ballistics for the SIG Sauer Ammunition line.

Click here to see our selection of SIG V-Crown bullets.

Reloaders Corner: Pressure Curves and Port Pressure – Part 2

Facebooktwittergoogle_pluspinterestyoutube

The following is a specially-adapted excerpt from the forthcoming book,” Top-Grade Ammo,” by author Glen Zediker, owner of Zediker Publishing. Click here to order.

Last time I gave a caution about respecting one of the differences between semi-auto and bolt-action rifles, and that was with respect to propellant burn rates. The summary reason for that is that different rate propellants will “peak” at different areas as the expanding gases and the bullet travel through the bore. Slower-burning propellants peak farther, and that means more pressure is available at the gas port location in an AR-15, for instance, as the bullet passes it. If the system is oversupplied, then the system is overworked.

Compared to ideal function when gas supply is delivered as engineered, mistimed peak pressures can result in the bolt unlocking too quickly and excessive bolt carrier velocity rearward. The system just gets hit too hard. The extractor tries to yank the case out of the chamber too soon, before the case is released from its grip on the chamber walls (from being expanded through firing). Spent-case condition shows a measurably more abused hull. Probably the worst popular example of these effects is the M1A. I’m doing an entire column or two on reloading for this beast. Essentially, a spent case from an M1A will show dimensions that don’t seem possible. These come from the bolt unlocking too quickly. AR-15s actually handle excessive pressure better than some other designs.

Always keep in mind that this is all happening in about 2 milliseconds. Average time a bullet spends in the barrel, for most modern centerfire rounds, is 0.002 seconds. Timing is everything.

Keeping in mind the behavior of a pressure curve, which is like a wave cresting, factors that influence the amount of gas-port pressure, using the same load, include barrel length, gas-port size, and gas-port location. When the bullet is sealing the bore, the longer the barrel, the more pressure is contained for a longer time. The smaller or larger the gas port size, the slower or faster the gas enters the system. The farther back or forward the port is located, the sooner or later. Bullet weight is a factor also: heavier bullets accelerate more slowly (and also the reason heavy bullets erode the chamber throat more than lighter bullets).

And, the amount of volume inside the bore has a huge influence on all this. That matters when we’re using another caliber than .224 in an AR-15 or .308 in a big-chassis AR (like an SR-25). For instance, in that rifle chambered for .243 Win., but retaining the gas system specifications (gas port size and location) of the .308 Win.–chambered rifle, there’s way more pressure only because there’s less space, less volume, in the bore. The opposite is usually true when we’re running an AR-15 with a larger caliber bullet.

Selecting a propellant with a suitable burning rate, which, again, is something in the vicinity of H4895, is really the only thing we can do on the loading bench to ensure that we’re not contributing to these symptoms. Beyond that, dealing with excessive pressure gets technical.

All my NRA Match Rifles, which usually have 26-inch barrels, get their gas ports moved forward one to two inches. These, of course, are custom-barreled. I also usually install an adjustable gas manifold.

Moving the port forward effectively delays the wave of gas moving through the bore, kind of repositioning its peak with respect to its outlet; there is more space available for expanding gases. It also allows a little slower-burning propellant, which can take more advantage of the longer barrel. It’s common in a similarly constructed AR-10 to get a port moved as much as 5 inches forward to accommodate a .243 Win. or .260 Rem. chambering.

The adjustable manifold allows some tuning. There are essentially two forms these take. One way is to restrict or limit the through-flow; the other just bleeds it off. I like the first kind the best.

Also, I have searched far and wide for a consensus on gas-port sizes, and came up empty.

All this changes with different chamberings and rifle configurations. Carbine-length barrels are particularly sensitive to port pressure because the port is located farther back.

There are a few surefire things that will alert you when your rifle is exhibiting “over-function” symptoms, such as spent-case condition showing excessively blown (extended) case shoulders, extractor marks on the case rim, and a generally explosive sensation in functioning.

In a more extreme circumstance, an over-accelerated carrier can “bounce” back from its rearmost travel so quickly that a round can’t present itself in time to be picked up by the bolt, or the bolt stop can’t engage quickly enough to hold the bolt carrier.

Sometimes what appears to be a “light” load is actually not. I’ve seen excess pressure leave a spent case in the chamber because the extractor lost its grip, and I’ve seen chunks pulled right off case rims. That’s severe. That’s also another cause for the “short-stroke” appearance of over-function: the extractor issue has slowed the carrier.

If you’re having any problems with “over-function,” solutions include retrofitting an adjustable manifold, increasing carrier mass, installing a stouter buffer spring. I do all those things on my rifles. Keep in mind that I am primarily a Service Rifle shooter, and I am trying to push an 80-grain bullet as fast as reasonably possible from a 20-inch barrel that can’t get the modifications mentioned. I know a thing or three about delaying bolt unlocking — I’ll cover more on this topic if you all want to know.

 

Sources:

Sun Devil Manufacturing

663 West 2nd Ave., Suite 16

Mesa, AZ 85210

(480) 833-9876

 

Medesha Firearms Ltd.

10326 E. Adobe Rd.

Mesa, AZ 85207

(480) 986-5876

 

Sierra Announces Five New SIG V-Crown Bullets

Facebooktwittergoogle_pluspinterestyoutube

Sierra SIG Sauer V-Crown Bullets Nov 2015

Sierra Bullets, in partnership with SIG Sauer, has announced the availability of five new members of the V-Crown self-defense-bullet line. The V-Crowns deliver Continue reading Sierra Announces Five New SIG V-Crown Bullets

Hodgdon’s Step-by-Step Loading Help

Facebooktwittergoogle_pluspinterestyoutube

Midsouth Shooters Supply sells a ton of Hodgdon powders, because, of course, the company makes great products our customers love. But Hodgdon powders are also popular because the company’s experts are willing to help folks get started in the craft or guide experienced hands toward new reloading ventures. Whether you’re new to reloading or a seasoned vet, there’s always something more to learn.

That’s where Hodgdon’s Reloading Education section comes in. The company has stockpiled a wealth of information that can help take your handloading to the next level. Over the next few weeks, we’re going to look at Hodgdon’s online system for building top-rate rifle, pistol, and shotgun loads and give you some pointers on how to make time-saving and money-conserving choices on brass, bullets, and powders.

Click here to see the landing page on which Hodgdon begins the education process.

Select the Reloading for Beginners tab to learn the basics, from the effect of crimp depth in shotshells to reloading the .223 to matching shot type and size to reloading data.

Midsouth also recommends you spend some time learning about Safety. Click that tab to brush up on the do’s and don’ts of reloading, starting with the basic reloading precautions created by the NRA.

Then, select the Tips and Tricks tab for informative posts on key topics in the reloading community.

Here’s a sample of some of the things you’ll find on the site:

Reloaders Corner: Pressure Curves for Semi-Automatic and Bolt-Action Rifles

Facebooktwittergoogle_pluspinterestyoutube

The following is a specially-adapted excerpt from the forthcoming book, Top-Grade Ammo, by author Glen Zediker, owner of Zediker Publishing.

When you’re handloading for semi-automatic rifles and bolt-action rifles, it’s helpful to realize they are not to be approached the same way. Continue reading Reloaders Corner: Pressure Curves for Semi-Automatic and Bolt-Action Rifles