Helmets - Bullet pings / Actual protection discussion

[LemoN]

I'm surprised that 7.62x25 was such a penetrating kick arse round.

If you come to think about it, the 7.62x25 has more powder load (longer amd wider than the 9x19, also a necked cartridge) and a smaller diameter bullet. Pretty logical that it's a relatively good penetrator compared to 9x19 and .45ACP.

 

[Floyd]

With a quick look at a generic ballistics chart one can see why as well:

[URL="http://www.aosurplus.com/ammo_chart.htm"][URL="http://www.aosurplus.com/ammo_chart.htm"][URL="http://www.aosurplus.com/ammo_chart.htm"][URL="http://www.aosurplus.com/ammo_chart.htm"][url]http://www.aosurplus.com/ammo_chart.htm[/URL][/URL][/URL][/URL][/URL] (Not the best site strictly for ballistics data as it lacks range velocity and energy. It was just handy.)



Muzzle Velocity in m/sec = MV
Muzzle Energy in joules = E

7.62x25  MV = 421  E = 499
   9x19  MV = 320  E = 412
.45 ACP  MV = 245  E = 450

The 7.62x25 packs a punch.

 

[Capt.Cool]

Haha yeah right. This video is classic propaganda --
I'm sure the troops at the front figured out pretty damn fast that their helmets didn't deflect bullets.

I am totally aware that this is propaganda!
But its an american vid! It shows a american bullet shot at a german helmet!

And if it does not penetrate its true, cause I dont think americans would like to do
positive propaganda for german equipment, right?!?!

 

[VariousNames]

With a quick look at a generic ballistics chart one can see why as well:

http://www.aosurplus.com/ammo_chart.htmhttp://www.aosurplus.com/ammo_chart.htm (Not the best site strictly for ballistics data as it lacks range velocity and energy. It was just handy.)



Muzzle Velocity in m/sec = MV
Muzzle Energy in joules = E

7.62x25  MV = 421  E = 499
   9x19  MV = 320  E = 412
.45 ACP  MV = 245  E = 450

The 7.62x25 packs a punch.

It's a high velocity round which is the biggest contributor to its penetration.

In terms of terminal effects, however, in spite of the energy/muzzle velocity, the most damaging rounds on that list go in the opposite direction, e.g:

.45 ACP > 9x19 > 7.62x25

Interestingly, PDWs like the MP7 and the P90 use this same principle. It's considered ideal for PDWs to combine high penetration in a small compact package (military combat involves body armor). Pistol rounds generally have ****y penetration relative to rifle rounds. Thus the designers made thin, high velocity rounds, essentially scaled down rifle calibers for PDWs. Inadequate as home defense rounds because their terminal effects are crap, but they have far greater penetration than an average pistol round, basically due to their dimensions. Compare:

9x19 pistol cartridge to 4.7x30mm PDW round found in MP7

Part of why the .357 magnum is such a monstrosity relative to other pistol calibers is its high velocity.

 

[VariousNames]

Yeah I highly doubt that a helmet would be stopping a military FMJ ~ 200 grain 7.92MM rnd at that distance. I just got a M48BO ( A yugo made k98k) and it kicks like a mule. Would probably put a hole in that helmet if you put the stock to the helmet and fired...

Forget that, even a .223 would go through it like a hot knife through butter.