Does an M14 really "turn cover into concealment"?
- Thread starter Andrew Wiggin
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The issue really falls around a math and physics problem, assuming all things being equal (same bullet design). Additionally their are two things to evaluate. the properties of the bullets and the properties of the material to be penetrated. On the bullet side, the mechanical energy(potential + kinetic) and its penetration property(will it hold together) is key. On the material side, the mass, tensile strength, and the elasticity or lack there of is key.
Small and fast is great until it hits something that is hard or harder with mass, then it dumps most of it energy very fast. Concrete is hard and it has very little, if at all, elasticity. However, those cinder bricks that were used, have air pockets and, in the video the OP provided, the brick was also hollow in the center. Fill the brick with sand and you'd likely see that the 5.56 would not perform very well at all. However, due to increased in kinetic energy, the 7.62, would fair much better against the same type brick.
In the videos with the steal armor plating - those are far from scientific evaluations and would not hold up to even slightest scrutiny as a valid evaluation, in my opinion.
Small and fast is great until it hits something that is hard or harder with mass, then it dumps most of it energy very fast. Concrete is hard and it has very little, if at all, elasticity. However, those cinder bricks that were used, have air pockets and, in the video the OP provided, the brick was also hollow in the center. Fill the brick with sand and you'd likely see that the 5.56 would not perform very well at all. However, due to increased in kinetic energy, the 7.62, would fair much better against the same type brick.
In the videos with the steal armor plating - those are far from scientific evaluations and would not hold up to even slightest scrutiny as a valid evaluation, in my opinion.
The rifle does nothing and has nothing whatever to do with it. A 7.62 x 51 Ball round will turn a cinder block(those are the bricks your mom's basement is built out of.) into dust at over 100 yards. So does .303 British Ball. As does any pre-5.56 military cartridge.
There's a Youtube video of a guy shooting one of the evil "green tip" 5.56 NATO rounds at a cinder block from a lot closer that 100 yards. Appears to go through, but does little to the block.
https://www.youtube.com/watch?v=oG43dU1tS88
So you need to know the difference between what is cover and what is concealment. And the difference between cartridges and rifles.
No need for AP to turn a brick to dust, but there is 7.62NATO AP. I believe your ATF decided is was too evil for you to have though.
Using the term 'old farts' when you mean experienced shooters is derogatory too.
There's a Youtube video of a guy shooting one of the evil "green tip" 5.56 NATO rounds at a cinder block from a lot closer that 100 yards. Appears to go through, but does little to the block.
https://www.youtube.com/watch?v=oG43dU1tS88
So you need to know the difference between what is cover and what is concealment. And the difference between cartridges and rifles.
No need for AP to turn a brick to dust, but there is 7.62NATO AP. I believe your ATF decided is was too evil for you to have though.
Using the term 'old farts' when you mean experienced shooters is derogatory too.
Andrew Wiggin
New member
Sorry. I've been camping so I couldn't reply.
Those concrete blocks are commonly for block fences here in Phoenix. This is just the first test in a series I plan to do. While I believe that 7.62x51mm probably can penetrate a bit more than 5.56x45mm, I think that the difference on real world objects is likely to be much less than the old farts claim. In this test both cartridges made it through. I'll go ahead and test a block filled with sand, as suggested, and I'll bet that both are stopped.
While there is probably a Goldilocks tree that will not stop a 7.62x51mm M80 but can stop 5.56x45mm M855, I suspect there are a great deal now objects (including trees) that can either stop both cartridges or stop neither cartridge.
ETA: I choose M80 and M855 because those are a: what I have on hand in quantity, and 2: the commonly issued FMJ for their respective rifles/machine guns.
Those concrete blocks are commonly for block fences here in Phoenix. This is just the first test in a series I plan to do. While I believe that 7.62x51mm probably can penetrate a bit more than 5.56x45mm, I think that the difference on real world objects is likely to be much less than the old farts claim. In this test both cartridges made it through. I'll go ahead and test a block filled with sand, as suggested, and I'll bet that both are stopped.
While there is probably a Goldilocks tree that will not stop a 7.62x51mm M80 but can stop 5.56x45mm M855, I suspect there are a great deal now objects (including trees) that can either stop both cartridges or stop neither cartridge.
ETA: I choose M80 and M855 because those are a: what I have on hand in quantity, and 2: the commonly issued FMJ for their respective rifles/machine guns.
Andrew Wiggin
New member
Numbers like velocity and sectional density?
Did you watch the video?
Did you watch the video?
I watched the video. Punching through a cinder block at short range isn't exactly stretching the performance envelope of either cartridge 
Hickock45 has a video of an M1A verses a block wall at 245 yards.
From experience with M60s and M240Bs verse M249s, once you get some range between the gun and target, the 7.62x51 ballistics are very nice to have. Of course it takes about a belt of 7.62 to do what a 50BMG can do in a ten round burst.
Compare and contrast these two videos, and the effects on target.
M1A
https://www.youtube.com/watch?feature=player_embedded&v=JwZPJgkF6G8
AR15
https://www.youtube.com/watch?feature=player_embedded&v=hQRmHVTze-g
Remember, the golden rule of fires is that if you aren't achieving the effect you want, just use more
Jimro
Hickock45 has a video of an M1A verses a block wall at 245 yards.
From experience with M60s and M240Bs verse M249s, once you get some range between the gun and target, the 7.62x51 ballistics are very nice to have. Of course it takes about a belt of 7.62 to do what a 50BMG can do in a ten round burst.
Compare and contrast these two videos, and the effects on target.
M1A
https://www.youtube.com/watch?feature=player_embedded&v=JwZPJgkF6G8
AR15
https://www.youtube.com/watch?feature=player_embedded&v=hQRmHVTze-g
Remember, the golden rule of fires is that if you aren't achieving the effect you want, just use more
Jimro
Andrew Wiggin
New member
The larger mass is a lot more useful at longer range. That's one area where I think there is little argument that the 7.62x51mm really shines.
kilimanjaro
New member
f = Ma, all you need to know.
Double Naught Spy
New member
"Turning cover into concealment" is another one of those gun phrases popular in our culture that really doesn't make sense. If the bullet goes through it, then it wasn't cover.
The M14 may be good at helping people realize that PERCEIVED cover is just concealment, but it doesn't turn cover into concealment.
Cover works both ways , if the bg has such good cover then he cant get a shot at you either . Iv alwasy trained to find a loop hole in the cover or waite for a turkey neck . One shot .
I know I saw a steel penatraiting test on one of the popular gun shows that showed 5.56 penatrate 1/4 "steel but would not penatrate 3/8ths " 7.62x51 did penatrate the 3/8ths . But there has been better comparison posted here already . I hadnt giving as much thought to shooting through stuff as I have finding a clear shot .
I know I saw a steel penatraiting test on one of the popular gun shows that showed 5.56 penatrate 1/4 "steel but would not penatrate 3/8ths " 7.62x51 did penatrate the 3/8ths . But there has been better comparison posted here already . I hadnt giving as much thought to shooting through stuff as I have finding a clear shot .
Andrew Wiggin
New member
Depends on the type of steel. 5.56mm can penetrate armor that is rated for 7.62x51mm.
https://youtu.be/oMYkEMhPsO8
https://youtu.be/oMYkEMhPsO8
johnwilliamson062
Moderator
I've been in the situation of thinking I had decent cover with 556 and X39 flying overhead. Then thinking I heard a 240 open up and my cover just diminished. Then hearing the distinct rhythm of an M2 and thinking I might as well be behind a Japanese Shoji panel.
Maybe one round going through the 556 can compare, but when it comes to knocking down walls I certainly give the larger rounds the edge.
Maybe one round going through the 556 can compare, but when it comes to knocking down walls I certainly give the larger rounds the edge.
Dragline45
New member
Yup, within a certain distance 5.56 reaches velocities high enough to punch through steel that 7.62x51 cant. Once that 5.56 round slows down enough though it will not penetrate. As the video said, velocity is king when defeating steel. This is actually the reason I sold my Level III steel plates for Level III+ since III+ will stop M193.
Andrew Wiggin
New member
If I remember right, that same guy tested III+ and not even .22-250 went through.
Those will penetrate all soft body armor.
They will not penetrate military ceramic SAPI plates. Nor will any of the rounds being discussed here.
So the fact that they won't penetrate steel body armor (not in use by any major military force that I am aware of) doesn't seem like a legitimate reason for Russia to abandon the x39 family of cartridges.
Jimro
Andrew Wiggin
New member
5.45x39mm will penetrate steel plate even better than M193 due to the high sectional density.
Springfield Armory museum in Springfield MA has some interesting displays
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A pair of them are penetration through hardwood, showing the effect of shooting an M1 rifle and an M14 rifle.
The amount of penetration the M1 rifle attained was surprising, even when I knew that rifles can shoot through tree trunks. I was still impressed.
The M14 was sobering in its superiority over the M1 rifle re: penetration through hardwood. In this era of TV and Movie "fact" surrounding firearms, I'm not sure it is wholly inaccurate to use the loose term 'turns cover into concealment' when talking about certain rounds.
"Perceived" is the keyword here. Perception is a person's reality. Otherwise experience wisdom and common sense would be everyone's default position.
.
A pair of them are penetration through hardwood, showing the effect of shooting an M1 rifle and an M14 rifle.
The amount of penetration the M1 rifle attained was surprising, even when I knew that rifles can shoot through tree trunks. I was still impressed.
The M14 was sobering in its superiority over the M1 rifle re: penetration through hardwood. In this era of TV and Movie "fact" surrounding firearms, I'm not sure it is wholly inaccurate to use the loose term 'turns cover into concealment' when talking about certain rounds.
"Perceived" is the keyword here. Perception is a person's reality. Otherwise experience wisdom and common sense would be everyone's default position.