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Does an M14 Really Turn Cover Into Concealment?

By Andrew Betts

M14

If you spend enough time at an outdoor range, especially on the weekdays when the retirees are there in force, you are certain to hear someone opine that they prefer the M14 to the AR/M16/M4 because it “turns cover into concealment”. This is usually in conjunction with their opinion that the DoD made a terrible error in moving to the 5.56x45mm, rather than the much more manly 7.62x51mm. No one can claim that the 7.62mm NATO does not have more power. The cartridge contains significantly more powder and it launches a heavier bullet at only moderately lower velocity. Is that extra power actually useful for penetrating cover, though? Does it really “turn cover into concealment”?

To answer that, we took a look at a few real world objects of varying composition. The question is not whether the 7.62mm penetrates more deeply than the 5.56mm. It is widely known that 7.62mm will penetrate more deeply in some materials such as wood, while 5.56mm can often penetrate steel plate at close range better. M193 55 gr FMJ can even defeat Level III armor plates that are rated for multiple 7.62x51mm M80 147 gr FMJ (https://youtu.be/QrWtgyFQ8LU). The claim that the old guys are making is that the M14 can kill a man who is hiding behind an object that would stop a 5.56mm. In other words, does a small difference in penetration depth really translate to a difference in whether a specific object will act as cover or not? If the cartridges are compared in terms of go/no-go, will the M14 really “turn cover into concealment”?

For the first test, we will consider concrete barriers. There are a variety of concrete walls, block walls, and other concrete barriers in the urban landscape that a person might take cover behind. The concrete varies somewhat in the ratios of the ingredients but all are composed of cement, sand, and sometimes larger aggregate. Regardless of the recipe, concrete has high compressive strength and low tensile strength. That means that it works very well for applications such as load bearing walls, but not so well for a second story floor. It resists being crushed but when bent, it cracks easily. That also means that it works pretty well to stop a bullet, but it is destroyed in the process. We tested two kinds of concrete. The first is a concrete block common to privacy fences, with lots of small aggregate and air voids.

The second is a concrete paver. While not as sturdy as a poured concrete wall, the paver is made from mostly cement and sand, with little aggregate and no air voids.

In both tests, neither round was completely stopped by the concrete barrier. While the 7.62mm did look more impressive, the 5.56mm also made it through and neither cartridge seemed to retain much ability to wound on the other side of the wall. That is to say, both would likely cause a painful wound but neither were likely to penetrate deeply enough to have a high probability of causing incapacitation. A bad guy on the other side of either of those barriers would have an awfully bad day to be sure, but he would likely have the opportunity to make your own day much shorter. To sum up, it is a very close race with little practical difference between the two cartridges.

Of course, an 8” thick, poured concrete wall with rebar reinforcement is likely to stop both rounds cold, but it is also outside our ability to test. There are almost infinite variations on the thickness and composition of concrete structures and some will certainly stop both cartridges while others will not stop either cartridge, as seen in the above tests. It would take substantial resources to conclusively identify exactly what sort of barriers could be penetrated by which cartridge and at what distance. For our more general and limited testing, the conclusion is that both cartridges can penetrate some concrete barriers. There may very well be a special Goldilocks barrier that is just thick enough to stop the 5.56mm but not the 7.62mm. From what we can see of this testing, it seems likely that such a barrier would also bleed so much energy from the 7.62mm as to render it nearly harmless, though. Both cartridges failed to fully penetrate a single water jug in this test so if the thickness of the concrete were increased to that magical point where 5.56mm was stopped but 7.62mm passed through, the 7.62mm would be even less energetic than was seen in this testing, which means a very minor wound.

Next, we will consider one of the few components on a motor vehicle that actually has a good chance of stopping a bullet: a brake rotor. Other than the drive train, the brake rotors (or drums) are one of a very few places where there is actually enough thick metal to have a reasonably good chance of stopping a bullet. Frame rails will usually stop handgun rounds but are unlikely to stop any rifle round and it is common knowledge that the body does next to nothing to stop a bullet. Conversely, the engine and transmission should stop nearly any man portable weapon short of an AT-4. Will the brake rotor be just thick enough to stop one cartridge, but not the other?

In this case, several rounds of both the 5.56mm and the 7.62mm were stopped. It is true that the 7.62mm looked to be a bit closer to getting through, based on the slight cracks on the back side of the disc, but the bottom line is that a person hiding behind that object would not have acquired any extra face holes from either cartridge.

Wood is one of the materials which 7.62mm is said to penetrate much more deeply than 5.56mm so we compared the two cartridges’ ability to penetrate a modest sized log.

On the one hand, the 7.62mm penetrated almost twice as much wood as the 5.56mm. On the other hand, both were stopped and you would need to find a log that was more than 2 ½” thick but less than 4” thick to be able to stop the 5.56mm but not the 7.62mm. Aside from the obvious problem that few people would consider a 4” stick to be “cover”, the difference here underscores something we have long suspected. It is true that 7.62mm can penetrate more deeply, but the difference is unlikely to make any substantive real world difference. That is to say, there are very few objects that are just thick enough to stop a 5.56mm but not thick enough to stop a 7.62mm. Most objects are either thick enough to stop both or thin enough to stop neither.

We did find one material that was soft enough to underscore the difference in a very definitive way: water. This is a test using a 55 gallon plastic drum filled with water as the barrier.

Finally, here is an object that very clearly stopped one bullet but not the other. If your target is taking cover behind a 55 gallon plastic drum full of water, 7.62x51mm can punch through it, while 5.56mm will probably be stopped. In the high speed video, it seems that the 7.62mm was not really moving along that quickly after passing through the barrel, though. It is possible that it would not be capable of doing much wounding after getting through the barrel, but we did not test for that, so the nod has to go to the 7.62mm for getting through.

It is also worth noting here that projectile construction could make a significant difference in any of these tests. If the rounds were changed to bonded soft points, it is possible that both rounds would have made it through the water. If the 7.62mm were a Hornady 155 gr AMAX, it is unlikely it would get through the barrel. There are a wide variety of bullet weights and designs available for both cartridges and some of them will substantially change the performance on these objects. We chose M80 and M855 because they are the commonly issued FMJ ammunition for their respective rifles. We chose a 16” barreled AR15 because it is a good compromise length and we did not have the time to test 11.5”, 14.5”, and 20” barrels. We also did not test at greater distance, where the 7.62mm is likely to have a larger advantage because hauling the test materials 200 yards down range is difficult, bothersome, and disruptive to other shooters. There are a variety of conditions that were not tested and those conditions could give more of an edge to one or the other cartridge.

Overall, most of the tests showed very little difference between the two cartridges. In every test but the water barrel, either both penetrated the test object or both were stopped. Ultimately, it does not appear that there is any evidence to support the unilateral claim that 7.62x51mm “turns cover into concealment”. There may be some very specific circumstances where this is true, but they appear to be the exception, rather than the rule. To be sure, this concept deserves quite a lot more testing. It would be nice to see the differences at range and through a variety of other materials such as live wood and poured concrete. Some day we may continue testing. It seems that the M14 is likely to develop a real, substantive advantage as range
increases because the greater mass and higher ballistic coefficient can carry more energy further down range. On the other hand, this sort of testing only compares a single round of one cartridge to a single round of the other but 7.62mm weighs twice as much and that means a person is likely to have twice as much 5.56mm. In that light, one round of 5.56mm may be just about as good as one round of 7.62mm but two rounds of 5.56mm are far better than one round of 7.62 in nearly any circumstance. The real take-away here is that nothing in the world of firearms and projectiles is nearly as simple as “A is better than B” and it appears that the statement “The M14 turns cover into concealment,” is more often false than it is true.

Related  further reading of 762 penetration

7.62 NATO, Turning cover into concealment since…. well, not as often as you may think.

Colt 6940 Piston Carbine Test & Review Part 1

The  idea that the piston operated AR15/M4  would be an improvement that fixes all of the perceived short comings of the weapon has been something that has gained ground in certain corners since the dubious “dust tests” and H&K marketing from a bit over 10 years ago now. Miss-use by users in the GWOT and careful lobbying by certain companies has put the idea that the DI system is sub-par in the minds of some of the lesser educated.   In fact ,if you did not know better you would think the piston operated AR15 did not exist until HK came out with the 416.    Truth is Colt had already developed a piston operated AR15 since the 60s and had been playing around with it ever since. If you look close at the front sight, you will see some details that pop up a lot later.

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Later Colt, in 2005-2006 colt started showing pictures of another piston gun they called the LE1020. It was a monolithic railed upper very close to the current 6940 uppers. It lacked the QD sockets,and some other small refinements but it was clear the idea was being refined. All this before others had started with their piston campaign.  Yes, colt had been making and refining piston AR15s for a long time. Getting it the way they wanted it before deciding to offer it.  We did not see the LE1020 hit the market back then because it was found the market and the Military was not that interested in a piston gun.  It took ignorant gun writers and HK marketing to convince a lot of people that they could not like without a piston operated M4.  Never mind some of those early piston ARs chewed up receiver extensions, suffered from carrier tilt, weighed a ton and were not very easy to modify.

If you are new to AR15s you may have missed the bright spike that was the peak of people wanting piston guns because so many believed a little dust caused a M4 to malfunction and History channel documentaries that were more or less HK 416 advertisements.  That has craze has evened out now a days and while some SOF use piston M4s, the rest of the army found out the M4 with its DI worked just fine witht some oil and not trying to use the M4 as a SAW.  But in that time, companies had some time to tweak the piston guns to get them to work right.  Among those was Colt, who refined their piston model from all those years ago before any one else had even thought about making a piston AR15.

With that, we come to the present day. A few weeks ago, Colt once again was nice enough to send me a shiny new Colt 6940Piston for my grubby little hands to test and abuse for other peoples amusement. We will take a look at it in this first part of a longer review and test. just to get to know it a little. stick our nose in its nooks and crannies and put on the old rubber glove and tell it to bend over so we can get to know it a little deeper….

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The Colt 6940P ( Piston) is essentially a regular 6940 from the outside. The lower is standard Colt milspec minus the full auto FCG of course. The buffer that comes with the P is the H2. This is standard issue with the gun as it comes with the the heavy SOCOM profile barrel we talk about in a moment.  The SOCOM profile M4A1 barrel is always combined with the H2 buffer in Colt models. Piston guns with standard A2 flash hiders will have a bit more felt recoil than DI guns, and the H2 buffer can smooth that out, Though to be clear that it not why it is in the gun.  As I said, with colt, the H2 buffer always is paired with the SOCOM barrel, but it is a nice side effect.

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Looking at the picture of the buffer you will note there is no shaved metal from carrier tilt or eaten up lowers which was common on some other companies piston conversions.

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As mentioned, the barrel is the SOCOM profile, which was  made for the use on M4A1 full auto carbines.  The cut flats a few inches from the front sight are for the M203 to mount around. The barrel is free floated in the monolithic upper. The free float 6040 uppers will give you every bit of accuracy the barrel is capable of. I have never seen a Colt monolithic upper that has given mediocre accuracy when using good ammo, but the piston parts may make a difference. We will see in part 2 with accuracy testing.

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The upper rail is standard 6940 and the lower rail removes the exact same way.  You can see just like the DI guns, this one has the QD sling points. The piston parts are hidden under the FF rail.

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The piston comes out very slick  and is retained neatly with a push pin much like those used for the lower. You simply push it to the side and slide the piston out.No muss no fuss.

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The piston is Colt’s design with the articulating link. Not much to say about it since its a piston. Very robust.

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Since we have a piston, we don’t need a gas carrier key.  The early Colt P guns had a bolt on part, just like the gas key, this was changed to the current model. It is machined out solid on the carrier . No bolts or staking to worry over. Not that you ever really had to worry about a colt stake job in the first place.   The Bolt carrier group fields strips for cleaning just like the standard non-piston   BCG

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The rear of the carrier has rails machined on it to make sure you get no carrier tilt. No tilt means your lower will not get chewed up like some of the early HK416 and conversion kits rushed out on the market.  The truth is, the AR16 was not meant to be a piston gun, so careful changes had to be made for it to work out in the long term. With the rails to the rear of the carrier and a steel block added to the upper receiver, tilt is a non issue on the 6940P.  In the picture below,  you can see the part added to the upper.  Buyers of even DI guns will notice this on newer 6940 DI guns and the 901 as there are plans to make piston 901 eventually and it simplifies production to make them all the same.

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Above is the upper with lower rail hand guard removed with piston and bolt carrier.

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From the outside, it looks like the regular 6940 until the educated eye looks at the front sight. The gun handles and balances no different, thought the SOCOM barrel adds a little more weight.  To get ready for long term hard shooting, accuracy testing and full auto torture tests, I have added my favorite TD grip and Colt factory ambi safeties.  For drills and general use it now has a CompM4 a B5 stock and a Knights  600 meter BUIS.  Part 2 of the review will be the accuracy testing for group, long range to the weapons extreme limit and more.  Full auto fire may be in part 2, or it may be moved to a part 3 for torture test and taking a look at cleaning the piston gun. Less fouling is often touted as one of  a piston gun’s biggest advantages so it is possible I do a part devoted to that.

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A rare failure, the broken AR15 forward assist.

Broken AR15 Forward Assist

Pictured above is the broken forward assist from my Colt 6933.

I’ve see a few forward assists break. Every time it has come as a surprise to the shooter. Usually what happens is a shot is fired, and the action ends up locked closed, and no one is able to open it using normal clearing techniques. In my case the action locked open after ejecting a shell.

It can be hard to diagnose a jam caused by a broken extractor simply because you can’t see that is what is preventing the bolt carrier from moving.

The best procedure we have found to free up a stuck bolt carrier from a broken forward assist is to:
1. Remove magazine, keep muzzle pointed in a safe direction.
2. Hold rifle with the ejection port down, barrel parallel to the ground.
3. Shake rifle while attempting to move bolt carrier.

Then usually it wont take much to get the action moving again. Immediately clear the chamber and remove the bolt carrier group from the action and remove any loose parts(like the forward assist pawl shown above).

Over the years, I have come to believe that the forward assist should be reserved for emergencies. In practice or on the range if a round does not chamber discard the round or inspect the firearm. I have met many(most former Army) that hit the forward assist after every reload. If your rifle isn’t chambering the round under its own power, there is something wrong with either the rifle or the ammo. Forward assists very rarely fail, but there is no point in slapping it around unless it is an emergency.

Designated Marskman Instructor Comments on the AR15 at 1,000 yard Article

This is from the comment section from the article about shooting the AR15 at 1,000 yards. The commenter offered some insight into the Army’s marksmanship levels and attitude.  I have offered the commenter a chance to elaborate and post more on the subject.  hopefully this will be expanded and he will come back to share his thoughts and experience in greater detail in more posts.   Below is the original post from Jose

Original post Jose was speaking about here

http://looserounds.com/2013/06/10/ar15-at-1000-yards-can-a-rack-grade-ar15-and-m855-make-1000-yard-hits/

Good on you Shawn. I’ve coached the last three consecutive All Army Small Arms champions. Before that I taught SDM for s number of years, still conduct the occasional course.
I’m not a distinguished rifleman (yet) but I’ve produced a number of them.
The M16A4 and M4 are woefully misunderstood by nearly all Soldiers. There are less than 200 Soldiers in the Army that I would consider “Riflemen” even the “multiple tours, combat arms NCO” is not a guarantee of any real skill at arms AT ALL. Soldiers are universally poorly skilled with their rifles. It’s appalling. But for such Soldiers, first you’d have to admit you have a problem. If they “qualify expert” they believe *that* somehow equals skill. I’d call that “familiarity.” 40/40 is easy, nothing to brag about, and is a ridiculously low standard. Most Soldiers never achieve even that embarrassingly low standard. If an NCO can’t get all of his squad to shoot “expert” he’s untrained.
My point is that most (but I’d wager closer to all) the criticism you may have received from Soldiers ought to be dismissed out of hand. They really are overconfident amateurs. Even in “Special Forces” units, that’s no guarantee of skill at arms.
That about sums it up. If I offended someone, good. Outshoot me.
The thing is that the M16/M4 is an EXCELLENT weapon and there are excellent 5.56mm cartridges. A Soldier doesn’t have to be a superhero to shoot really well with it either. We trained many female Soldiers that had no problem striking a steel silhouette target, 14″ wide and 40″ tall, at 760 meters, with iron sights on her M16A2. I can drop names, ranks, class dates. With the M4 and ACOG, SDM Students routinely hit the same target at 800 to 830 meters – 1st round hits.
In our SDM classes, we spent so much time at 500 and 600 on the KD range, that 300 was a welcomed and easy target engagement for them. Yet in units many Soldiers will not engage the 3 exposures of the 300 meter target, preferring to save those three rounds for the closer targets when they miss the first shot, so they can re-engage the ‘easy’ targets. They’re all easy!
I want to share a couple of things, there’s somebody out there reading this that will heed this advice, I promise it can make you a dramatically better shooter.
When shooting for precision with rack grade Army M16’s or M4’s there is one method that works. DO NOT EVER USE A SLING OF ANY KIND TO “LOCK IN” “SNAP IN” OR OTHERWISE PULL ON THE SLING SWIVEL. The AR in a rack grade condition does not have a free floating barrel. The upper receiver is made of a zinc and aluminium alloy, the barrel is hard steel. Pulling on the sling is like making a giant torque wrench, moving the strike if the round several inches just at 100 yards! Any weight or pressure on the handguards moves the barrel.
Don’t touch the handguards or use a sling if you want the most out of a rack grade rifle.
Use the magazine, preferably a 30 rounder, as a monpod. Place the palm of your non firing hand (not your fingers) on the flat front face of the magwell. Spread your elbows and get nice and low and stable. The non firing palm exerts firm rearward pressure on the rifle.
There’s more to it, but that’s the biggest challenge you’re having now. Great job on the test
Enjoy.

SCAR-L Review And Thoughts

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A test and review of the SCAR-L by us has been long in coming. Over the past few days, we did finally got a chance to test and evaluate a SCAR. I shot it in some drills and did accuracy testing of it in my normal manner or off of a bench using sand bags.

The SCAR probably needs not introduction at this point in time. It was developed by FN to be what they hoped would be the replacement for the M4 carbine. Well. That did not happen, turns out it was not all that much better as claimed and the 5.56 guns issued out to certain elite units, were turned back in for M4s.  That does not mean it is a bad gun or unreliable, just that it was not considered to really be much of an improvement over the excellent M4 family of weapons.  Thought the 7.62 model has had more success.

So, to see for ourselves and those who may be thinking about getting one, lets take a look at it.

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One of the bigger hyped things about the SCAR is the folding stock and the reciprocating charging handle. The gun came to me with the charging handle on the right side. I found this intolerable. If you are a lefty it would not be bad at all. But most of us are not.  The charging handle was swapped to the left side where it was much better for handling. Then I found out that it was in the perfect place for me to tear the skin off my knuckles when charging the weapon if it had any optic mount on it.  I had to be careful about this after a couple of times learning the slow way.

The Stock folding to the side does make it very compact, and unlike the AK type. it is also adjustable for length. I found it not to be bad at all. But not really all that great either. In the past there has been people reporting the stock to have some durability issues, but I had since heard that was over come on newer models.   The stock also had a adjustable cheek rest I found marginally useful while I had it.  Though I am sure it would be of benefit with some optics.

One thing to remember if you buy one, is that it will not take a military standard spec AR15 grip. So if you want to use something else you have to do some fitting with the grip or gun….

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The optic that came with the gun is a Elcan Specter.  I am not going to review it,since this is mainly about the gun. but it had a a max power of 4x and could switch to 1x and a red dot along with a few other  gem jams.  It was mounted with the ARMS throw levers that excelled at skinning my knuckles when using the charging handle on the left side.

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I shot the SCAR at 100 yards using my usual method.  First used 77 grain match ammo.  You can see the results above.   I have no explanation for the left side flyer.   The gun’s barrel has a 1/7 inch twist. so it can stabilize the heavy rounds.

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The above target it labeled both dots as 55gr Tactical Urban Rifle ammo, but that was a mistake on my part. I was talking to a friend while doing it and made a mistake.  right side is 55gr. and the left is M855.

Notice the gun fired the 77 grain ammo high and a little to the right and shot the lighter stuff a little more to the left.  007

In rapid fire drills, I was surprised by it.  The guns muzzle break is very effective. It is very flat and mild in recoil. Though it has plenty of unpleasant blast like any brake. After the first magazine I remarked it felt almost like a 22LR.  The gun with that brake was calmer and flatter in recoil than any surefire brake I have used on a weapon of like size and barrel length and contour.   Speaking of the barrel contour, it is thin. Thinner than I would ever want. Especially on a gun meant for heavy use.  It got hot very fast and stayed hot.     In addition to the pleasant recoil mitigating brake, this gun has a really good trigger.  I have forgotten the make of the trigger but will get the info and update this with it as soon as I can.  But the smooth match trigger and the muzzle device made the gun something easy to shoot.  I can see why some use it in 3 gun type events.      With the grip provided on the gun though. it was impossible for me to work the safety without changing my grip with the firing hand,

A few other points and opinions that may be unique to me.  The rail section of the gun as is, is not enough. If you need more than a weapon light on the the stock gun, you are going to need a VFG.    It is no wonder that companies came out with rail extenders for the weapon so fast.   Another thing is, I was not a fan of the way it field strips as compared to the AR15.  Also the front sight was not as intuitive as I would have preferred. Of course all this is probably due to me having much more time with AR15s and the hear set up for them.    A warning to the “fit and finish ” and ” I want my guns to look good!” crowd.  The color of the finish does not match. You will have about 3 different shades of FDE. so if you cry yourself to sleep at night because you have brass marks on your case deflectors, then you better not buy this one.

I enjoyed shooting the SCAR-L.  But in my opinion, it is certainly not better than or more easy to use over an M4. I do not feel it to be more accurate than a good Ar15 either ( at least this model).  I thought the stock left a lot to be desired. Reloading it was not much different than on a M4  thought the safety has a shorter arc to travel from safe to fire.  Sad to say the grip used on the gun did not allow me to see for myself if it was really an advantage, I am doubtful it really is a huge advantage even if it seems like it would be.    If you want to be different or want one for whatever reason and have the money and think you will  love it. then you are probably right.   but it is not for me.

If I had to make a recommendation on the SCAR weapons, I would suggest following  the Army Rangers example and get the SCAR-H in 7.62 instead

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One last detail. I used an ATLAS bipod on the gun over the 3 days time with the gun.  I thought it had some nice features, and was certainly well made, but I do not consider it as handy as a decent Harris Bipod. I would not buy one with my own money. And if given one, I would not use it for anything that  needed to be able to deploy it fast.