armor vs ammo - known facts

[meketrefe]

This is for anyone who wants to learn more to be safe fom thugs who might attack civilians and police so ...what is effective to survive and defend ourselves and loved ones ?

This came up at the Thread About Nothing so by @carpediem 's request we can discuss what to use.

What about a wildcat round built off of a .308, fired from an AR and has enough velocity to penetrate an AR-500 plate at 50 yards?

Like I said 7.62x51 AP is a nice round so there is no need to really design anything new.

 

[Podmonkey]

What level of body armor? Just about any centerfire rifle round will penetrate the level II or even IIIA armor most typically encountered. Try to scrounge up some M2 AP, it's perfectly legal to buy still right? Which I don't think is true for M993 AP (7.62x51) and I know m995 AP (5.556x45) is a no go.
Honestly I think regular ol 7.62 NATO FMJ would be perfectly adequate.

 

[meketrefe]

Those are designed for military grade body armor where the typical FMJ from power rifles will not penetrate.
They are also great as car stoppers as they go through engine blocks like knife through butter.
Of course the ideal is a 50 caliber AP to stop trucks but I am saying for a manageable AR or other small firearm.

I just searched in youtube and found this guy shooting an AR500 plate with 308 NATO AP surplus round. (Towards the end)


Speed is also the key. That is why the 5.56 is a much better round than the classic AK FMJ (or blackout) even at close
or mid range. Once you get to certain types of steel and glass the light for caliber slow moving rounds are not a great
idea. This is why the old AK round got retired from service from the main military forces. Russia, China, etc...

 

[meketrefe]

Here stopping gansters South African Style. This operator uses AP rounds to stop the gansters trucks.

 

[meketrefe]

Here the trusty FAL + 308 stopping a cartel's car in Brazil...

 

[spat]

What level of body armor? Just about any centerfire rifle round will penetrate the level II or even IIIA armor most typically encountered. Try to scrounge up some M2 AP, it's perfectly legal to buy still right? Which I don't think is true for M993 AP (7.62x51) and I know m995 AP (5.556x45) is a no go.
Honestly I think regular ol 7.62 NATO FMJ would be perfectly adequate.

Loaded ammo is a no-go, but I think you can still get the projectiles and load your own.

Need to find some .188 tungsten welding electrodes, and make some aluminum bushings to heat shrink on for them to come up to caliber. I bet you could get close to the max AP capability of any common caliber that way.....

 

[meketrefe]

Loaded ammo is a no-go, but I think you can still get the projectiles and load your own.

Need to find some .188 tungsten welding electrodes, and make some aluminum bushings to heat shrink on for them to come up to caliber. I bet you could get close to the max AP capability of any common caliber that way.....

Black tip is being sold at the gun shows. But yes you can order bullets and roll your own if you want.

 

[Podmonkey]

I am posting this here because I think it shows that bullet construction is at least as important as velocity for armor penetration. The 13.2 TuF round used here is not on the same level as the .50 BMG or even the British .55 Boys.

 

[carpediem]

I started a thread about the body armor thing. There was a video I saw about the standard 55gr ball 5.56 fired out of a longer barrel penetrating an AR 500 plate quite easily. The same rifle fires a penetrator round and it fails to pierce the plate. I am curious of a .308 could be necked down to a caliber that could pierce the plate without a steel core.

 

[Podmonkey]

I started a thread about the body armor thing. There was a video I saw about the standard 55gr ball 5.56 fired out of a longer barrel penetrating an AR 500 plate quite easily. The same rifle fires a penetrator round and it fails to pierce the plate. I am curious of a .308 could be necked down to a caliber that could pierce the plate without a steel core.

Define "penetrator round" If M855 then yes, it has been established that m193 will punch steel better. At shorter range at least.

 

[carpediem]

Yes M855

 

[spat]

I started a thread about the body armor thing. There was a video I saw about the standard 55gr ball 5.56 fired out of a longer barrel penetrating an AR 500 plate quite easily. The same rifle fires a penetrator round and it fails to pierce the plate. I am curious of a .308 could be necked down to a caliber that could pierce the plate without a steel core.

Specifying AR500 without a thickness is useless.

1/4" AR500 is pretty common, and easy to defeat. 1/2" is pretty common and will stop most things short of 50BMG AP. 3/4 isn't too hard to find, and I think that *will* stop 50 AP.

AR500 can be ordered up to 2" and you'll need something like a GAU-8 with DU to get through that.

 

[Marine Cpl]

Most bad guys don't go around wearing that kind of body armor that weighs in excess of 25 lbs. for those that have a concern.

 

[Marine Cpl]

Define "penetrator round" If M855 then yes, it has been established that m193 will punch steel better. At shorter range at least.

Due to speed. It has to have some weight. Whatever that is, then speed is what determines penetration.

The 55 gr will beat the 62 gr in that category at all ranges because I'll always be faster until both drop velocity to the point that neither penetrate.

Grain alone doesn't penetrate or else a shotgun slug would.

 

[Cippee]

I fired black tip and silver tip 308 rounds out of a win mag. The black tip penetrated better it went through 1.4" of cold rold steel 1.5" of 7075 aluminum and .35 inches of ar500 steel. I will post pics tomorrow of the plates. So out of a ar-10 or 308 riffle you have no chance. The 155 grain bullets out the win mag were moving at about 3400 fps.

 

[meketrefe]

Just to make sure we do not confuse steel core, steel tip, bimetal, and all those with AP that have some sort of slug made of tungsten carbide.
The steel core can penetrate very well in certain barriers where the fmjs will fail but it is not a substitute for the AP not even the fastest cartriges.
It is a nice trade-off and 5.56 will penetrate body armor up to certain level and it will go throug some pretty bad ass steel like hot rolled steel up to
1/2" or even thicker where for example the AK47 round, blackout, pistol, etc... will fail.
But for example will not punch through AR500 plates. That is the AP function for the hardest barrier / armor.

 

[Podmonkey]

Also AP rounds have poor terminal performance in soft targets.

 

[Podmonkey]

^ Oh, you like that do you, Mr Frying Pan?

 

[meketrefe]

Also AP rounds have poor terminal performance in soft targets.

Correct. The idea is that they have to go through some sort of barrier to come apart and between the fragments and
the slug they are more effective on a soft target behind if that is required but otherwise they would put pin hole wounding.
Another role is as car/truck stoppers and other anti material roles proportional to the power of the round.
The 308 is a pretty bad ass round already as it was the 30-06 AP predecessor.

 

[Marine Cpl]

^ Oh, you like that do you, Mr Frying Pan?

I only like truth. Don't fall into taking things personal like most do here.

 

[Podmonkey]

I only like truth. Don't fall into taking things personal like most do here.

See, now your being catty again. Do you want a hug? I think you need a hug.

 

[Marine Cpl]

The same goes with barrier penetration of regular hard objects. What may penetrate at 1200 fps with a 124 gr with no problem may now have problems penetrating the same barrier if it's a 147 gr going at 950 fps.

 

[meketrefe]

Due to speed. It has to have some weight. Whatever that is, then speed is what determines penetration.

The 55 gr will beat the 62 gr in that category at all ranges because I'll always be faster until both drop velocity to the point that neither penetrate.

Grain alone doesn't penetrate or else a shotgun slug would.

Not really. The 62gr will retain speed out to 500 yards and also with the additional momentum, although not by much it is enough to make
a difference. 55gr FMJ continue to be effective for many uses and inexpensive but we cannot rely anymore in the original intent that
was tumbling and fragmentation. All other things being equal the 62gr will come on top always.
The modern design based on Liberty's ammunition arrohead design stolen by the US-ARMY (now settled through courts) proved to be so
efficient in intermediate and hard barrier that the same design principle has been adopted for the 30 caliber. At some point the 62gr 5.56 had
more hard barrier penetration capability at a distance than the 308 itself. I believe it was 300 yards according to Army papers from tests but I might be wrong. You can find the documents online.
IMO the lead free was a big mistake and they should have adopted the best of both designs that would probably would have been a small lead core perhaps nosler partition stile yet preserve the arrowhead design. This would allow the round to be shorter and either reduce the pressure that is at its limit right now or increase power but will work exactly the same as soon as the rear portion of the round stayed together w/o fragmentation. I don't see a reason why it would not work based on bonded designs and partion themselves when punched in very hard targets.
In any case the 62gr is the standard right now and IMO the minimum you want for a 5.56 for tactical, military, defense use.
Again the 55gr is cheap, plentiful and will work great for a lot of roles but it doesn't work as originally designed in modern rifles and tactics.

This doesn't have anything to do with AP designs that fall into a different category.

 

[Marine Cpl]

See, now your being catty again. Do you want a hug? I think you need a hug.

Nah. I just got the sense that you didn't like that adding grain made things worse.

 

[Marine Cpl]

Not really. The 62gr will retain speed out to 500 yards and also with the additional momentum, although not by much it is enough to make
a difference. 55gr FMJ continue to be effective for many uses and inexpensive but we cannot rely anymore in the original intent that
was tumbling and fragmentation. All other things being equal the 62gr will come on top always.
The modern design based on Liberty's ammunition arrohead design stolen by the US-ARMY (now settled through courts) proved to be so
efficient in intermediate and hard barrier that the same design principle has been adopted for the 30 caliber. At some point the 62gr 5.56 had
more hard barrier penetration capability at a distance than the 308 itself. I believe it was 300 yards according to Army papers from tests but I might be wrong. You can find the documents online.
IMO the lead free was a big mistake and they should have adopted the best of both designs that would probably would have been a small lead core perhaps nosler partition stile yet preserve the arrowhead design. This would allow the round to be shorter and either reduce the pressure that is at its limit right now or increase power but will work exactly the same as soon as the rear portion of the round stayed together w/o fragmentation. I don't see a reason why it would not work based on bonded designs and partion themselves when punched in very hard targets.
In any case the 62gr is the standard right now and IMO the minimum you want for a 5.56 for tactical, military, defense use.
Again the 55gr is cheap, plentiful and will work great for a lot of roles but it doesn't work as originally designed in modern rifles and tactics.

This doesn't have anything to do with AP designs that fall into a different category.

55 gr solid copper TSX would be a lot different than a regular FMJ that relies on fragmentation.

 

[Podmonkey]

Nah. I just got the sense that you didn't like that adding grain made things worse.

I don't care dude, this is an academic discussion. I would really love to do some hard testing on this, I don't think the data we are drawing on is accounting for all the variables.

 

[Marine Cpl]

I don't care dude, this is an academic discussion. I would really love to donsome hard testing on this, I don't think the data we are drawing on is accounting for all the variables.

Speed penetrates no matter what given a set amount of weight in a certain caliber. Did you see the video where the 50 gr 9mm going at 2000 fps penetrate armor while the 115's, 124's, and 147's didn't?

The frying pan video shows that as well. The .380 going at 900 fps couldn't penetrate the pan while the 115 of the same diameter going a few hundred fps faster went through like butter.

 

[meketrefe]

The same goes with barrier penetration of regular hard objects. What may penetrate at 1200 fps with a 124 gr with no problem may now have problems penetrating the same barrier of it's a 147 gr going at 950 fps.

If one is really concerned about advanced tactics and barrier/body armor penetration one is going to look into calibers like
the 357SIG, 10mm, 5.7, etc.. with light stout bullet designs and extra speed.
you also have things like 7H21 and 7H31 9mm Luger developed under the "Grach" project.
We are talking about rounds that can achieve close to 2000fps or more and punch thorugh IIIA like knife through butter
where all other rounds like 10mm, 45ACP, 38 special, etc.. will fail.

The whole reasoning for the US Secret service adopting the 357SIG and 5.7 is to tackle targets with body armor or through
doors and glass w/o deflection aside from the additional firepower that is also necessary for those kind of tactics.

 

[Marine Cpl]

If one is really concerned about advanced tactics and barrier/body armor penetration one is going to look into calibers like
the 357SIG, 10mm, 5.7, etc.. with light stout bullet designs and extra speed.
you also have things like 7H21 and 7H31 9mm Luger developed under the "Grach" project.
We are talking about rounds that can achieve close to 2000fps or more and punch thorugh IIIA like knife through butter
where all other rounds like 10mm, 45ACP, 38 special, etc.. will fail.

The whole reasoning for the US Secret service adopting the 357SIG and 5.7 is to tackle targets with body armor or through
doors and glass w/o deflection aside from the additional firepower that is also necessary for those kind of tactics.

I know that. My point is given what you have in that one caliber, speed penetrates more.

Of course a Sig would do better. It's a 9mm with more velocity.

The .380 may not penetrate x amount of inches of steel but the 124 gr at 1200 fps could. That same 124 gr may not penetrate thicker steel but the 125 gr Sig going at 1500 fps will. That same Sig round may not penetrate even thicker steel yet the 125 gr from a .357 Magnum from a 6 inch barrel going at 1650 fps will. They are all 9mm's per say with different cases going at much higher speed.

 

[meketrefe]

55 gr solid copper TSX would be a lot different than a regular FMJ that relies on fragmentation.

OK lets take a 55gr and 62gr TSX ...

The 62gr wins because it is not just the speed that is more than enough but the extra momentum. In terms of punching through and killing
potential there might be a very small difference but the 62gr always wins.


Ballistics Results - 55gr tsx
Range (yards) Velocity (fps) Energy (ft.-lb.) Trajectory (in) Come UP in MOA Come UP in Mils Wind Drift (in) Wind Drift in MOA Wind Drift in Mils
Muzzle 3200 1250 -1.5 0 0 0 0 0
100 2739 916 0 0 0 0 0 0
200 2322 658 -3.2 1.5 0.4 0 0 0
300 1943 461 -12.9 4.1 1.2 0 0 0
400 1607 315 -31.9 7.6 2.2 0 0 0
500 1325 214 -64.6 12.3 3.6 0 0 0

Ballistics Results - 62gr tsx
Range (yards) Velocity (fps) Energy (ft.-lb.) Trajectory (in) Come UP in MOA Come UP in Mils Wind Drift (in) Wind Drift in MOA Wind Drift in Mils
Muzzle 3000 1239 -1.5 0 0 0 0 0
100 2674 984 0 0 0 0 0 0
200 2371 774 -3.4 1.6 0.5 0 0 0
300 2088 600 -13 4.1 1.2 0 0 0
400 1826 459 -30.6 7.3 2.1 0 0 0
500 1588 347 -58.8 11.2 3.3 0 0 0