Robin
.577 Tyrannosaur.
Choose your ground and know it.
Robin
armor vs ammo - known facts
- Thread starter meketrefe
- Start date
Robin
Marine Cpl
.577 Tyrannosaur.
For the average slub that frequents this forum and doesn't have access to armor penetrating rounds, a .40 grain would do the job.
Now I'm not saying that I'll work at 200 yards, I'm just saying at 10 ft in the house, it works.
Speed penetrates.
Now I'm not saying that I'll work at 200 yards, I'm just saying at 10 ft in the house, it works.
Speed penetrates.
Uzi
.308 Win
Robin, maybe one day I'll be as wise enough to understand the powerful meanings in your comments and replies you share on this forum. Meanwhile until then....
I r dizzy nows.
spat
.700 Nitro Express
I was on my way to Magnus's house.....
carpediem
.338 Win Mag
Go to the mall with him. You will be sure to run into a squad of ISIS terrorists or some Spetznaz parachuting into the courtyard and no doubt there will be body armor!
carpediem
.338 Win Mag
I don't know but it should be fast enough to pen the plates consistently.
Marine Cpl
.577 Tyrannosaur.
I know you are looking for .308 but in the meantime, if you have a .223, a 45 grain varmint round will punch through consistently at short range.
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carpediem
.338 Win Mag
If I found a .223 round that was consistent in results, I could be comfortable with it.
Marine Cpl
.577 Tyrannosaur.
Well he shot that 45 grain with a 20 inch, 18 inch, 16 inch, and a 14.5 inch and it went through. It failed however with a 11.5 inch barrel. The velocity was cut too short with that barrel.
Here were his numbers with the 45 grain.
20": 3,569 fps
18": 3,497 fps
16": 3,295 fps
14.5": 3,238 fps
11.5": 3,023 fps
carpediem
.338 Win Mag
AR 500 is rated for what, 3100 F.P.S. ?
Marine Cpl
.577 Tyrannosaur.
Honestly, I don't know.
carpediem
.338 Win Mag
From AR500 web site;
Armor Level Level III+
Armor Threat Rating Level III+ multi-hit protection against 5.56x45 M193, 5.56x45 M855/SS109 at 3,100 FPS (+/- 30FPS), 7.62x51 M80 Ball (ie .308) at 3,000 FPS (+/- 30FPS), and 7.62x51 AP (Black Tip) at 2,800 FPS (+/- 30FPS)
Armor Dimensions 10"x12"
Armor Construction Material Ballistic steel core
Armor Shelf Life 20 Years
Armor Thickness 0.26"
Armor Level Level III+
Armor Threat Rating Level III+ multi-hit protection against 5.56x45 M193, 5.56x45 M855/SS109 at 3,100 FPS (+/- 30FPS), 7.62x51 M80 Ball (ie .308) at 3,000 FPS (+/- 30FPS), and 7.62x51 AP (Black Tip) at 2,800 FPS (+/- 30FPS)
Armor Dimensions 10"x12"
Armor Construction Material Ballistic steel core
Armor Shelf Life 20 Years
Armor Thickness 0.26"
Acer-m14
20×102mm Vulcan
just aim at the main vain 
Marine Cpl
.577 Tyrannosaur.
Well, this proves that increases in speed and not grain is the key to penetration. If you look at the specs and all of the videos posted, when you up the grain, speed can be decreased somewhat but it still needs to be up there close to the threshold for the round to go through.
The guy in the video above consistently penetrated it with a 45 grain .223 until the barrel was too short and the speed was under the threshold. An increase in grain up to .308 did nothing.
'Bout that, yes.
meketrefe
.450/400 Nitro Ex
We can see the speed rating is arbitrary because the bullet grain and construction has a lot to do with it.
Also it would be impossible to rate everything so they advertise common calibers at average distances
shot with average firearms. They do not include calibers and distances that can punch the body armor
since this doesn't help with their marketing.
Marine Cpl
.577 Tyrannosaur.
You can have a solid steel projectile at a high grain but if the speed is not there, it won't penetrate. It still has to be somewhat close to the threshold of about 3000 fps more or less with a few hundred fps.
You can construct a pointed 125 grain .357 Sig of solid steel going at 1500 fps and I'll fail compared to a 45 grain .223 going at 3300 fps that'll go through.
Grain and construction is 1/3rd of the equation. Speed is the other 2/3rds.
carpediem
.338 Win Mag
I think the thing here is, and this relates to my initial question, speed and grain work together as is obviously the case. .308 has to hit a slightly lower velocity to defeat a .25 plate than .223, and the heavier .30-06 still slightly less. Now, that being a given, I want an AR style rifle that can reliably defeat .25 at short range. Therefore, velocity at the muzzle and at 10 yards needs to be well above the penetration velocity to mitigate any reductions in velocity caused by any variables, as well as cycling the rifle. I don't see the .308, from a 16" barrel in an AR, as being well above the threshold. I don't know for sure, but it seems suspect. However, if a .223 leaves the muzzle in excess of 4000 fps, even a variable of +\- 50 fps still renders it in the velocity "go zone". That is my point. For reliable and effective hits to an armored target, muzzle velocity needs to well exceed penetration velocity at the anticipated effective range. Penetrators help to mitigate some of the velocity loss by being effective at transferring energy to the target with minimal loss to material deformation. I don't want to rely on a penetrator. So thus my suggestion of a necked down .308 to like a .223 that uses a standard 55 grain projectile. Maybe even a standard .308 with a .55 grain accelerator type round, but at short range it likely wouldn't work.
Marine Cpl
.577 Tyrannosaur.
A 20 inch barrel with a .45 grain puts you at about 450 fps over the 3100 fps threshold.
Those 45 grainers went through like butter.
carpediem
.338 Win Mag
I should've put this in the prepping section. The only scenario I ever see this being needed is in the event of an EMP or solar flare or some other nasty event where if you stay put, you may be confronted by people in plates at a surprise close range. It isn't for the alphabet agencies or law enforcement, but rather defense against some of the clowns featured on the prepping shows.
carpediem
.338 Win Mag
Good video. The only thing is he used a base coat only plate. I wonder how they would do on a full coat plate. Is that varmint round commercially available?
Marine Cpl
.577 Tyrannosaur.
Winchester has one rated at 3500 fps. I looked up gel tests though and they only do about 8 inches. May not be enough to hit vitals. Don't know. Your idea is probably better with the necked down .308.
carpediem
.338 Win Mag
I just wonder where you could ever get someone to load up a bunch of ammo and you would need a barrel which, I imagine due to the high velocity, would need a high twist rate rifling. Do they make custom barrels like that. Somebody must, for a price.
meketrefe
.450/400 Nitro Ex
I think there are two perspectives to this:
- One scientific
- The other practical.
From the scientific stand point the research of what the specific plates can take from different calibers, rifles, range, angles, etc.. including the most exotic alternatives.
From the practical stand point is the effectiveness of the specific plates at the average ranges, with the average
rifles with the different ammunition available commercial or surplus. Those slight difference in caliber, weight
and construction might seem little but they might be the difference between 5 yards or 50 yards range and
also having enough material after fragmentation to be able to do some significant wounding.
Folks worried about the challenge of body armor train on the tactics that give them more control that is
to shoot above or below the armor w/o missing.
16" carbine is hardly the best choice for supersonic ammunition no matter what caliber. There are cartridges
optimized for 14 inches and shorter but not the best choices.
A 308W in 16" does not make much sense and 18" is a much better choice for all around use. Even for 223
6.8 it gives some nice extra speed in virtually the same package. A 18" barrel with a shorty brake is as long
as a 16" with a longer brake.
A 55gr sabot for a 308 doesn't make a lot of sense as the plastic doesn't like hot barrels and might mess
up your gas port.
If you think about it a 7.62x39 or a 6.8 even better when loaded with 80gr bullets solid or fmj will achieve
close to 3200fps and have a tad more mass and momentum to deliver. There are a few decent fmjs available
and the x39 could inexpensibly be looaded with tokarev bullets and popular faster powders.
The GS and cuttin edge solid bullets come out screaming in a popular and reliable 6.8.
I would still go with the 18" barrel for extra speed.
I would stay away from exotic calibers and hiper velocity varmint rounds that can only be achieved by
very long varmint barrels and they also are barrel burners like the 22-250.
- One scientific
- The other practical.
From the scientific stand point the research of what the specific plates can take from different calibers, rifles, range, angles, etc.. including the most exotic alternatives.
From the practical stand point is the effectiveness of the specific plates at the average ranges, with the average
rifles with the different ammunition available commercial or surplus. Those slight difference in caliber, weight
and construction might seem little but they might be the difference between 5 yards or 50 yards range and
also having enough material after fragmentation to be able to do some significant wounding.
Folks worried about the challenge of body armor train on the tactics that give them more control that is
to shoot above or below the armor w/o missing.
16" carbine is hardly the best choice for supersonic ammunition no matter what caliber. There are cartridges
optimized for 14 inches and shorter but not the best choices.
A 308W in 16" does not make much sense and 18" is a much better choice for all around use. Even for 223
6.8 it gives some nice extra speed in virtually the same package. A 18" barrel with a shorty brake is as long
as a 16" with a longer brake.
A 55gr sabot for a 308 doesn't make a lot of sense as the plastic doesn't like hot barrels and might mess
up your gas port.
If you think about it a 7.62x39 or a 6.8 even better when loaded with 80gr bullets solid or fmj will achieve
close to 3200fps and have a tad more mass and momentum to deliver. There are a few decent fmjs available
and the x39 could inexpensibly be looaded with tokarev bullets and popular faster powders.
The GS and cuttin edge solid bullets come out screaming in a popular and reliable 6.8.
I would still go with the 18" barrel for extra speed.
I would stay away from exotic calibers and hiper velocity varmint rounds that can only be achieved by
very long varmint barrels and they also are barrel burners like the 22-250.
Marine Cpl
.577 Tyrannosaur.
Did you see the video above? The 45 gr went through with a 20, 18, 16, and 14.5 inch barrel. It finally failed at an 11.5 inch. Then a standard NATO .308 was shot at the same plate and it failed too.
Low grain will do nothing at a distance but still do something at CQB ranges. You can get those low grainers and keep them in magazines for a specific purpose of CQB only.
meketrefe
.450/400 Nitro Ex
Will,
Yes I saw that video.
The low grain and high speed alone is not enough to get the best possible results.
Here is your same favorite youtuber with the same plate with a 11" AR and M855A1.
The 45 grain failed with that type of barrel.
This guy seems totally unscientific and arbitrary but it gives the general idea I guess.
In order to put things into perspective and based on what we see here this is the range
a typical 16" AR will give you to defeat the type III armor.
Speeds from 16" barreled upper.
Ballistics Results - 223 45gr varmint
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 3300 1088 -1.5 0 0 0 0 0
25 3179 1010 -0.8 3 0.9 0.1 0.4 0.1
50 3063 937 -0.3 0.5 0.2 0.3 0.6 0.2
75 2950 869 0 0 0 0.7 0.9 0.3
100 2839 805 0 0 0 1.3 1.2 0.4
125 2732 746 -0.3 0.2 0.1 2 1.6 0.5
150 2627 689 -0.8 0.5 0.1 3 1.9 0.5
175 2524 637 -1.7 0.9 0.3 4.1 2.2 0.6
200 2424 587 -2.9 1.4 0.4 5.4 2.6 0.8
Ballistics Results - 5.56 62gr M885A1
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 3050 1281 -1.5 0 0 0 0 0
25 2985 1227 -0.7 2.8 0.8 0.1 0.3 0.1
50 2922 1175 -0.2 0.5 0.1 0.2 0.4 0.1
75 2860 1126 0 0 0 0.5 0.6 0.2
100 2798 1078 0 0 0 0.8 0.8 0.2
125 2737 1032 -0.3 0.2 0.1 1.2 0.9 0.3
150 2678 987 -0.9 0.6 0.2 1.8 1.1 0.3
175 2619 944 -1.8 1 0.3 2.4 1.3 0.4
200 2560 902 -3 1.4 0.4 3.2 1.5 0.4
with the 16" uppers...
The 45gr varmint around 25 yards perhaps a bit more. will fail with the short 11" upper.
not sure who would use such type of stupid firearms anyway.
The 62gr service round will give a range of 50 yards perhaps a bit more. will work with the 11"
upper at close ranges. The M193 will also fail with both uppers and will only work with the bolt action at short range like the other youtuber showed.
For type III+ Body armor we have the 308 service round M80A1 that like 5.56 was designed
for the next level of tasks.
The bullet construction has a lot to do with this and like I said we can speculate all day long but the
militaries of the world have already invested millions of dollars and tested millions of rounds to figure out what is best.
It makes fun threads but there is nothing to be invented here in the forums.
If surplus is not found and 5.56 is desired then I would use the 50gr TSX loaded to the max and that is a good stout bullet for glass although a 62gr TTSX is a lot more versatile and ballistically efficient for all sort of use.
Otherwise for short barreled carbines the 6.8 with 80gr solids is hard to beat.
Marine Cpl
.577 Tyrannosaur.
Meke, you are hyper focused on distance. Nobody is looking to punch through armor at 50 yards and beyond. We aren't military. This would be at CQB distances of 15 yards and below in ones home. The 45 grain wouldn't be a replacement for a 62 gr for general purpose. It would be a specialty round used for that short range purpose of punching through armor.
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meketrefe
.450/400 Nitro Ex
Agree. I think then the 45grain will work fine from a 16 or 18" barrel.
It is a simple solution. For CBQ even better than the TSX so they reduce the potential
of collateral damage due to over penetration when going through walls and stuff.
I think it doesn't get much easier than that.
People often ask what is the best alternative caliber to run from 223 bolts and magazines
and I always say the 6x45 but also the 223 itself if one looks at the proper ammunition
for the task at hand.
For average use the black hills 77gr TMK leaves the 7.62x39 and blackout in the dust
in terms of ballistic performance.
These varmint will do the trick for the taks at hand.
...I still like the power of the 6.8. In a 16" carbine makes a lot more sense than the 308
itself. But it is a more involved caliber than any service round that is for sure.
meketrefe
.450/400 Nitro Ex
Another good one from south Africa.