REVIEW: MantisX: The Little Training Gizmo That Could

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This new training aid is worth well more than its cost in ammo. Find out what it is…

MantisX

by Frank Winn, Guns & Gear Editor
NRA America’s 1st Freedom

How enthusiastic would you be about a device that could turn you into a better pistol (or rifle) shooter in a hurry; weighed essentially nothing; worked on a huge variety of firearms; played no favorites by gender, stature, handedness (or hat-size, for that matter); worked in both dry- and live-fire modes; and could be had for a few week’s worth of pocket change?

Yeah — us too. So we present the MantisX Firearms Training System.

Physically, it’s an underwhelming sort of kit: A bland-looking Picatinny-attachable component (packed in the smallest Pelican case we’ve ever seen) comprises a compact sensor, and is accompanied by a single sheet of instructions and a USB-to-mini-USB charging cable. But unfold that sheet of paper, and you’ll start to cheer up, we promise. Eight steps that would fit legibly on both sides of a business card may be all you’ll ever read about the MantisX.

While we have suspicions about the need behind the complexity of the nuts and bolts, the concept behind the device is simple. Step One of those instructions is to get the brains to your phone — a free App Store or Google Play download — and Step Two puts the device on your rail. Next come prompted and self-terminating connection and calibration steps, and now you’re ready to train. Just push “start,” and you’re rolling. (Unless you’re at the range, remember to make sure a dry-fire session is truly dry: NO LIVE AMMO IN THE SAME ROOM AS YOU ARE.)

The sensor and your smart device are now monitoring the movements of your pistol in near real time. The data stream that the sensor sends is stripped of the crucial milliseconds around the hammer or striker fall, and the segment compared to the “still” calibration position. Large-amplitude movements like cycling and actual shots are filtered out. The result is shot-by-shot analysis of your movements in generating the trigger press. Individual shots are scored, and the string as a whole is averaged on a 0-to-100 scale (100 demonstrates you’ve introduced no extraneous movement).

A lot of what you’ll see on your smart device in “Train” mode will remind you of a “Common Errors and Corrections” target that’s been around for years and years — one of those teaching aids that we love and hate at the same time. Pretty much everybody has seen these. They’re a spider-web-looking sort of target with a very pronounced center aim point, and labels that really give them away. They’re intended to help you identify and correct many gripping-architecture/mechanics problems that, if repeated, cause shots to stray in predictable ways. So far, so good. Their shortcomings are more difficult to apprehend, and the biggest are inseparably tandem: They have handedness (different for righties and lefties) built in, and this means they’re truly helpful only when you shoot on them with the named, single hand. As this is a huge departure from modern technique — both hands pressed together around the pistol grip just for starters — it’s no wonder their utility begins to fade. Certainly, their cues to remedy misdirected shots become less useful.

MantisX screeen

You can use your MantisX system in this way. In fact, knock yourself out: You will develop a fine trigger press with either hand. But don’t think for a second that the MantisX software shares the limitations of paper predecessors. Take a look at the “Learn” screens, and you’ll see that two-handed technique has been accounted for in the software. Whether the training suggestions are utterly perfect or not will soon be an afterthought. The real power is in revealing those tiny corrupting movements you had no idea you were making.

Two additional “Train” mode displays are where this becomes clear. The first is a line graph that looks a little bland on first inspection: Your string gets plotted left to right on the zero-to-100 scale as shots are made. Overlaid on this is a running average, recomputed and displayed as a line across the inevitable zig-zag of the successive, individual shots.

With an efficiency matched by nothing else we know, the MantisX gets you closer to repeatability in that all-important press.

This isn’t as ho-hum as it may sound, though it’s a little hard to describe why. We think the graphical presentation of the relative stillness of each shot is simply more obvious in the line plot: Shots that feel very similar will measure quite differently and — sometimes glaringly — illustrate the disastrous compounding of flaws that routinely spoils what feels like a technically sound shot. Nothing makes this clearer than an ugly, obvious 20- or even 40-point bounce from one press to the next. But stick with it, and this is where the near-magic happens. Between the MantisX sensor, software and your brain, a feedback loop is built, and we think you’ll be as astonished and impressed as we were how rapidly those infuriating swings begin to moderate. With an efficiency matched by nothing else we know, the MantisX gets you closer to repeatability in that all-important press.

MantisX

The third Train-mode screen gives even better detail on variations in one crucial sense. While it goes back to the “bucket” display mode where shots are grouped by error type, it shows the degree of error, rather than a simple count. Reading this is therefore a bit more subtle: If you have small, concentric slivers all around the center, your technique is likely very sound. The mistakes you’re making are causing very small angular deviations, and are approaching irreducible levels that reflect biologic immutables (pulse, respiration, etc.), not technique blunders.

If your pattern is more spoke-like — with larger/deeper arcs more scattered — then your score will be lower, too. You may have fewer errors, but their magnitude is such that they’ll have big(ger) impacts on downrange results.

While it’s easy to get excited about the actual shooting benefits of the MantisX system, it’d be an injustice to overlook some other fine attributes. A favorite is the charging method: The supplied cable lets you charge your sensor in any handy USB. We have no idea why there isn’t more of this in small devices of every type.

Next is that charging port itself. If you plan to do mostly dryfire work and have a pistol to which you’ll leave the sensor mounted (don’t forget — it works with CO2 and Airsoft too), such a mount can be made with the port accessible; that is, pointing forward to make plug-in dead easy. If you are using the sensor in live fire, you’ll be well-advised to turn the charging connection rearward so that carbon and other detritus don’t find their way into the connector. Just remember, this is parameter for the sensor, and creates push/pull assessment errors if not set on the “Settings” screen.

We can hear some of you thinking, by the way. “Gee, what would it be like on my rifle?” That is easily answered in two ways. First, we tried it, and it works just fine, though obviously the technique tips are mostly meaningless because grip is so different. But in terms of telling you how “quiet” you are physically at the moment you break the shot, it’s grand. Second, and not coincidentally, MantisX tells us that a rifle version of the software is already well along and due this summer.

A “History” mode is built into the MantisX software, too, and it’s about as self-explanatory as it could be. It stores each string as a bar graph in 0-to-100 scale, and contains the individual “Train” mode results (all three plots). It divvies them up by “live,” “dry” and “all,” as well as presenting some summary statistics. All are shareable as well.

We expect it’s clear that the more we fiddle with the MantisX, the more we like it. It’s clever, reliable and affordable, and will allow disproportionately rapid improvement for modest investments along several axes. But make no mistake: Its genius is not merely in forging some new paradigm, but also in refocusing and capitalizing on a time-tested one. It will put the fun back in dry fire. And if we’re honest, the more seasoned you get, the more boring this becomes. Heck, the MantisX even allows this to become a mildly competitive pursuit, if you like.

As to a new paradigm, we’d suggest it does this too. Nothing in (LOUD) shouting distance allows a reconnection between dry and live practice like the MantisX system. Making one pay dividends for the other has never been frankly transparent, and we think that’s about to change.

If you’ll take our advice, don’t be on the tail end of finding out.

MantisX unit

Visit MantisX site HERE
MSRP of the MantisX Firearms Training Systems is $149.99

RELOADERS CORNER: REALLY Understanding Case Neck Sizing

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Determining and setting the correct case neck diameter is a critical, crucial step in the handloading process: Here’s all you need to know!

sizing die bushing

Glen Zediker

Here’s another I get (too many) questions about, and when I say “too many” that’s not at all a complaint, just a concern… This next hopefully will eliminate any and all confusions about this important step, and decision, in the reloading process.

Basics: A cartridge case neck expands in firing to release the bullet. If the load delivers adequate pressure, it can expand to the full diameter allowed by that portion of the rifle chamber. That diameter depends on the reamer used. After expansion and contraction, the case neck will, no doubt, be a bigger diameter than what it was before being fired.

Back to it: To get a handle on this important dimension, the first step is tools. As always. A caliper that reads to 0.001 inches will suffice.

You need to find three outside diameter numbers: fired case neck diameter, sized case neck diameter, loaded case neck diameter. If you know the loaded case neck diameter then it’s likewise easy to find out the case wall thickness, or at least an average on it if the necks aren’t perfectly uniform (and they won’t likely be unless they’ve been full-on outside case neck turned).

Case neck sizing diagram
“All the math” works in either direction. Here’s how.

A fired case neck has to be sized back down to a dimension that will retain a bullet from unwanted movement (slippage) in the reloaded round. Case neck “tension” isn’t really an accurate term, in my mind, so I prefer to talk about “constriction.” The reason is that making a case neck diameter smaller and smaller does not, after a point, add any additional grip to the bullet. Once it’s gotten beyond maybe 0.005 inches, it’s just increasing the resistance to bullet seating not increasing the amount of tension or retention of the case neck against the bullet. The bullet is resizing the case neck, and probably getting its jacket damaged in the process. If more grip is needed, that’s where crimping comes in…and that’s (literally) another story.

IMPORTANT
Always, always, account for the “spring-back.” That is in the nature of the alloy used to make cases. If brass is sized to a smaller diameter it will spring back plus 0.001 inches bigger than the tool used; if it’s expanded to a bigger diameter, it will spring back (contract) to 0.001 inches smaller than the tool used. This is always true! The exception is that as brass hardens with age, it can spring back a little more.

How much constriction should there be? For a semi-auto, 0.003 is adequate; I recommend 0.004. For a bolt-action, I use and recommend 0.002, and 0.001 usually is adequate unless the rifle is a hard-kicker. See, the main (main) influence of more resistance in bullet seating is to, as mentioned, set up enough gripping tension to prevent unwanted bullet movement. Unwanted movement can come from two main sources: contact and inertia. Contact is if and when the bullet tip meets any resistance in feeding, and gets pushed back. Intertia comes from the operation and cycling of the firearm. If there’s enough force generated via recoil, the bullets in rounds remaining in a magazine can move from flowing forces. However! That also works literally in the other way: in a semi-auto the inertial force transmitted through a round being chambered can set the bullet out: the case stops but the bullet keeps moving. I’ve seen (measured) that happen with AR15s and (even more) AR-10/SR-25s especially when loading the first round in. Put in a loaded magazine, trip the bolt stop, and, wham, all that mass moves forward and slams to a stop. Retract the bolt and out comes a case with no bullet… Or, more usually, out comes a case with the bullet seated out farther (longer overall length). Never, ever, set a constriction level on the lighter side for either of these guns.

Most seem to hold a belief that the lower the case neck constriction the better the accuracy. Can’t prove that by me or mine. If there’s too much constriction, as mentioned, the bullet jacket can be damaged and possibly the bullet slightly resized (depending on its material constitution) and those could cause accuracy hiccups. If it’s a semi-auto and constriction is inadequate, the likewise aforementioned bullet movement forward, which is very unlikely to be consistent, can create accuracy issues, no doubt. My own load tests have shown me that velocities get more consistent at 0.003-0.004 as compared to 0.001-0.002.

Benchrest competitors use virtually zero constriction, but as with each and every thing “they” do, it works only because it’s only possible via the extremely precise machining work done both in rifle chambering and case preparation. It is not, decidedly not, something anyone else can or should attempt even in an off-the-shelf single-shot. As always: I focus here, and in my books, on “the rest of us” when it comes to reloading tool setup and tactics. Folks who have normal rifles and use them in normal ways. And folks who don’t want to have problems.

So, find out what you have right now by determining the three influential diameters talked about at the start of this article. Most factory standard full-length sizing die sets will produce between 0.002 and 0.003 constriction. Getting more is easy: chuck up the expander/decapper stem in an electric drill (I use oiled emery cloth wrapped around a stone), and carefully reduce the expander body diameter by the needed amount, or contact the manufacturer to see about getting an undersized part. I’ve done that.

polish expander
It’s easy to increase case neck constriction if you’re running a conventional sizing die setup that incorporates an expander or sizing button. Just make the button diameter smaller; then it won’t open up the outside-sized case neck as much as it is withdrawn from the die and over the expander.

If you want less constriction than you’re currently getting, about the only way to do that one is hit up a local machinist and get the neck area in the die opened by the desired amount (considering always the 0.001 spring-back). Or get a bushing-style die…

Redding S Die
It’s not perfectly necessary to use an inside case neck expanding tool if you’re using a bushing-style die. I think it’s wise for a multitude of reasons I’ve gone on about in the past, and may should again, but if the math is carefully done, and the cases are all same lot, outside neck reduction will result in consistent inside case neck diameter sizing. Example: Case neck wall thickness is 0.012, outside sized case neck diameter is 0.246 (from using, remember, a 0.245 bushing), then the inside case neck diameter will be 0.222, and that will be a 0.002 amount of bullet constriction (0.224 caliber bullet).

The bushing-style design has removable bushings available in specific diameters. Pick the one you want to suit the brass you use. If you run an inside case neck expanding appliance along with a bushing die, usually a sizing-die-mounted “expander ball” or sizing button, make sure you’re getting at least 0.002 expansion from that device. Example: the (outside) sized case neck diameter should be sufficiently reduced to provide an inside sized case neck diameter at least 0.002 smaller than the diameter of the inside sizing appliance. That’s done as a matter of consistency and correctness that will account for small differences in case neck wall thicknesses. And when you change brass lots and certainly brands, measure again and do the math again! Thicker or thinner case neck walls make a big difference in the size bushing needed.

Check out a few ideas at Midsouth HERE

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

D.C. Appeals Court Strikes Down ‘Good Reason’ Licensing Scheme

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“Unconstitutional” is what a federal appeals court has ruled on the D.C. gun law that says people must show “good reason” to have concealed handgun permits.

The Second Amendment is sufficient reason itself to issue permits, according to the 2-1 ruling released Tuesday July 25, by the U.S. Court of Appeals for the D.C. Circuit.

“In fact, the Amendment’s core at a minimum shields the typically situated citizen’s ability to carry common arms generally,” wrote Judge Thomas B. Griffith in the ruling on the case Wrenn v. District of Columbia.

Subsequently, the appeals court instructed lower courts to block the D.C. law with permanent injunctions. City officials indicated they’re exploring an appeal, while gun-control groups claim the ruling shrinks public safety in the nation’s capital.

D.C. gun laws are among the strictest in the U.S., but they’ve also faced several legal challenges in the last few years, said Kirk Evans, President of U.S. & Texas LawShield.

Evans noted that one landmark pro-gun victory was District of Columbia v. Heller in 2008 in which the U.S. Supreme Court—voting 5 to 4—struck down D.C.’s ban on handguns. Then, in 2014, another federal court prevented a proposed ban on carrying guns in public.

The D.C. Council—the enclave’s municipal government—responded by creating the “good reason” rule, which only issued permits to citizens who could prove they faced legitimate threats, Evans said.

“Simply residing in one of the District’s high-crime neighborhoods was not considered ‘good reason,’” Evans said. “This was not unnoticed by at least one member of Congress who complained colleagues were unarmed when a gunman shot up their ball practice in June.”

But, according to the appeals court’s decision, the “good reason” rule negated what the Supreme Court decided in Heller.

“The District’s good-reason law is necessarily a total ban on exercises of that constitutional right for most D.C. residents,” Judge Griffith wrote. “That’s enough to sink this law under (Heller).

Second Amendment advocates praised the latest ruling, including Alan Gottlieb, founder and executive vice president of the Second Amendment Foundation (SAF).

He said the ruling “contains some powerful language that affirms what we’ve argued for many years, that requiring a so-called ‘good-cause’ to exercise a constitutionally-protected right does not pass the legal smell test.”

Gottlieb added, “We are particularly pleased that the opinion makes it clear that the Second Amendment’s core generally covers carrying in public for self-defense.”

In the days after the ruling it was too early to tell how far the case would rise through the appeals process. The Supreme Court in June declined to consider another Second Amendment case, Peruta v. California, in which the 9th U.S. Circuit Court of Appeals agreed with a San Diego County law requiring gun owners to prove they have “good cause” to apply for concealed carry permits.

But Gottlieb said the latest victory in D.C. spurs confidence among Second Amendment advocates.

“To say we are delighted with the ruling would be an understatement,” Gottlieb said. “We are simply more encouraged to keep fighting, winning firearms freedom one lawsuit at a time.” — Bill Miller, Contributor, Texas & U.S. Law Shield blog

 

 

Check out these other great articles from U.S. Law Shield and click here to become a member:

 

The “purple paint law” became official in Texas on September 1, 1997. The law doesn’t appear to be common knowledge for every hunter in the Lone Star State, even though Texas hunting regulations describe it.
Can your employer restrict your ability to carry firearms at the workplace? Click to watch Emily Taylor, Independent Program Attorney with Walker & Byington, explain that in Texas, employers call the shots regarding workplace self-defense.
In this excerpt from a U.S. Law Shield News live report, watch Emily Taylor, independent program attorney with Walker & Byington, discuss the ground rules for carrying firearms into restaurants and bars. Click the video below to find out the significant differences between blue signs and red signs in Texas establishments, and how getting those colors crossed up could lead to some orange jumpsuit time.   If you would like to see these reports live on Facebook, click here to join the Texas Law Shield Facebook page and sign up for live notifications.

Campus Carry Part II Kicks Off at Texas Community and Junior Colleges

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The application of the state’s Campus Carry Law at community and junior colleges across Texas kicked off with a whimper—not a bang—on Tuesday (Aug. 1), to no surprise of TSRA Legislative Director Alice Tripp.

Texas LawShield Independent Program Attorney Edwin Walker visited with TSRA Legislative Director Alice Tripp in Austin earlier this year. 

“This effort started in 2007 and we’ve gone through four sessions of the Legislature and 10 public hearings,” said Tripp, who works closely with legislators as a representative of the Texas State Rifle Association.

“It has required a lot of work and effort.

“Now we will focus on making sure the state colleges follow the letter of the law,” she added, noting that every regular session of the Legislature colleges must send a report about their specific rules and regulations pertaining to the law and why they created them.

She said dire predictions of problems by the anti-gun crowd have proven to be groundless, just as when the law took effect at four-year public colleges on Aug. 1, 2016.

 

History

“There have been firearms on campuses since 1996—in the parking lots, on the grounds, in the dorms—this just opens up carrying firearms into buildings and classrooms.

“I am sure that students have been sitting next to someone carrying a handgun into a classroom all along. They were just doing it without permission—now they have permission,” she said.

Tripp pointed out that the negative attention on the issue has been focused mainly on students carrying firearms, while the driving force behind the effort to allow licensed carry on campus has come from faculty and staff members at the institutions of higher learning.

“What the faculty and staff members have told us is that they wanted to feel safe walking to their car in the parking lot after dark or in other areas where they might face a threat,” she said.

With the backing and support of the TSRA, state Senator Brian Birdwell, R-Granbury, filled SB 11, also known as the Campus Carry Law. It passed during the 2015 Legislative session.

 

Incidents

Tripp noted that incidents related to the implementation of the law last year at four-year public colleges have been limited to one accidental discharge where no one was injured and a couple of cases where licensed concealed-carry holders inadvertently entered restricted areas.

 

Campus Carry Legal Issues

On the legal side of the issue, three University of Texas at Austin professors sued the state and the university after enactment of the Campus Carry Law, claiming that the potential presence of guns in classrooms has a chilling effect on class discussion.

A federal judge rejected their claims, ruling that the professors failed to present any “concrete evidence to substantiate their fears.”

Colleges may ban or restrict firearms from certain areas of the campuses. The Legislature must review these restrictions every other year.

There was at least one demonstration opposing the implementation of the state law at community and junior colleges on Tuesday. It was a one-man protest by a San Antonio College geography instructor.

 

Minor Pushback

According to the San Antonio Express-News, the 60-year-old instructor conducted classes on Tuesday while wearing a Kevlar helmet and a flak jacket in his protest of the law.

Reaction on the comments page of the paper was mostly negative. One reader wrote that the instructor’s action was a “melodramatic and buffoonish spectacle in protest of the constitutional right of law-abiding citizens to defend themselves.” —by Ralph Winingham, Contributor, U.S. and Texas LawShield blog

 

 

Check out these other great articles from U.S. Law Shield and click here to become a member:

 

The “purple paint law” became official in Texas on September 1, 1997. The law doesn’t appear to be common knowledge for every hunter in the Lone Star State, even though Texas hunting regulations describe it.
Can your employer restrict your ability to carry firearms at the workplace? Click to watch Emily Taylor, Independent Program Attorney with Walker & Byington, explain that in Texas, employers call the shots regarding workplace self-defense.
In this excerpt from a U.S. Law Shield News live report, watch Emily Taylor, independent program attorney with Walker & Byington, discuss the ground rules for carrying firearms into restaurants and bars. Click the video below to find out the significant differences between blue signs and red signs in Texas establishments, and how getting those colors crossed up could lead to some orange jumpsuit time.   If you would like to see these reports live on Facebook, click here to join the Texas Law Shield Facebook page and sign up for live notifications.

NRA Statement on Trump Administration’s Aggressive Enforcement of Federal Firearm Laws

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NRA applauds Trump administration and its loyal Pro-Second-Amendment record to help American citizens take a stand in the face of rising crime. Read more…

trump

Source: NRA-ILA

Fairfax, Va. — Three months after President Donald Trump signed an executive order to crack down on illegal firearm possession, prosecutions of these crimes have risen by 23 percent. Violent criminals are now facing consequences for their illegal actions. At the same time, the Second Amendment rights of law-abiding gun owners are being respected under the Trump administration.

“The National Rifle Association applauds President Donald Trump and Attorney General Jeff Sessions for understanding that prosecuting violent criminals and protecting the rights of law-abiding gun owners are not mutually exclusive ideas,” said Chris W. Cox, executive director, National Rifle Association Institute for Legislative Action. “The Department of Justice report released today shows the administration’s commitment to getting violent criminals and gang members off our streets. After suffering an all-time low during the Obama administration, federal prosecutions of illegal firearm possession are now being taken seriously.”
The facts:
Charges of unlawful possession of a gun — mostly by convicted felons — are up 23 percent in the second quarter of 2017 from the same time period in 2016.

The number of defendants charged with the crime of using a firearm in a crime of violence or drug trafficking has increased by 10 percent.

The DOJ is on pace to prosecute the highest number of federal firearms cases since 2005.
During the Obama administration, federal prosecutions against individuals attempting to illegally buy a firearm dropped 40 percent.

During the Obama administration, prosecutions of unlawful possession of a firearm by a person subject to a court order dropped a whopping 66 percent.

“This report demonstrates that President Trump and Attorney General Sessions are making America safe again,” Cox concluded. “This is a complete reversal from the eight long years of the Obama administration, which ignored violent criminals while trying to destroy the rights of law-abiding gun owners.”

Established in 1871, the National Rifle Association is America’s oldest civil rights and sportsmen’s group. More than five million members strong, NRA continues to uphold the Second Amendment and advocates enforcement of existing laws against violent offenders to reduce crime. The Association remains the nation’s leader in firearm education and training for law-abiding gun owners, law enforcement and the armed services. Be sure to follow the NRA on Facebook at NRA on Facebook and Twitter @NRA.

SKILLS: Riflescopes: Lens Coatings

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Lens coatings provide superior optical clarlty and utility. Here’s how and why…

coated lenses

Source: NRAFamily.org

In any optical system, some light is lost through reflection each time the light passes through a glass-to-air surface. The light loss can be significant in multi-element riflescopes; as much as 50 percent of the light may be lost to reflection as it passes through an uncoated lens system.

In the 1940s, it was discovered that magnesium flouride coatings on lenses would increase light transmission, color fidelity and image brightness considerably. Today, nearly all modern scopes have coated lenses that transmit from 95 to 99 percent of the light that enters the objective lens.

Coatings such as zinc sulfide and zirconium oxide are used, often in combination with magnesium flouride. A coated lens will appear tinted when viewed from the side. The exact color may vary from blue, green, purple, red or gold. Abrasion-resistant coatings have been developed for the exterior lens surfaces of modern riflescopes. Water-shedding coatings have also been developed.

Various levels of coating can be applied to lenses ranging from a single layer of magnesium flouride on the exterior objective and ocular surfaces, to as many as 15 layers or more on every surface of every lens. Typically, coating layers are only a few ten-thousandths of an inch thick.

The term “fully coated” when applied to a riflescope usually means that all lens-to-air surfaces have at least one coating layer. This includes the interior lens systems as well as the exterior.
The term “multi-coated” or “multiple-layer coated” signifies that multiple coating layers have been applied to some, but not all, lens surfaces. Normally, this means that only the outer lens surfaces have been multi-coated. “Fully multi-coated” signifies multiple coatings on all lens-to-air surfaces.

Lower-priced scopes may have from one to five lens-coating layers while more expensive scopes may have as many as 15 or even more. In lower-priced scopes, only the outside surface of the objective (front) and ocular (rear) lenses are coated. Higher-quality scopes have all internal and external lens surfaces multi-coated.

How many layers are enough? That depends on the quality of the lens system and the intended purpose of the scope. Adding more layers of coating rapidly reaches the point of diminishing returns, but on a high-quality scope where maximum light transmission and image fidelity are necessary, 15 layers of coating can be easily justified.