308 vs 7.62 NATO: Huge Difference On Steel

I was in the military, specializing in armaments. The military literature mentioned that the 7.62 max pressure was 55,000 psi. If you read deeper into the file, it also mentioned that pressure was measured with copper crusher method. Now referred to as CUP. later, when transducers become the standard way to measure pressure, the industry adopted the system of referring to pressures as either CUP or psi. The military reference to 55,000 psi has caused many to believe that 7.62x51 is loaded to a lower pressure. No so. The limits for 308 and 7.62 are about the same - about 62,000 psi, as measured with a transducer. In practice, ammo of both flavours is typically around 56,000 psi, although I have found a few lots of 308 (Winchester Supreme match and IVI Lot 631) at 62,000 psi. Both were tested because they were causing problems in some rifles. The testing handbook specifies where the chamber pressure is to be measured. It varies from caliber to caliber. And sometimes (as in 7.62 -308) the place the pressure is measured is different in the two systems. If the place of measurement is the same, you can convert CUP to PSI mathematically, like converting MPH to KPH. But if the place of measurement is different, the two values bear no relationship to each other. There are some difference in the ammo specs - SAAMI vs. Military. The military case has a stronger, harder case head, so as to withstand violent extraction of automatic rifles. Military ammo has a muzzle flash spec. SAAMI does not. Military ammo will have a sealant in the neck. SAAMI does not. The lead core can vary in antimony content (hardness) and jacket thickness can vary as well, with military bullets being hard and commercial ammo being anything the maker finds easy to make. This test I watched just compared two different brands of ammo and assumed that the difference was due to NATO v Commercial. No so. Just brand A v brand B

I'm a reloader of 308 and want people to understand that NATO rounds are tested using a different method then US ammo manufactures, that is why the pressures are different, the real test is using the same powder. it's the powder and bullet that make the difference

I would love to see a 7.62x51 and 7.62x54r comparison on that steel system you’ve got. Great system for being able to grasp the meaning behind the velocity numbers

I think if your plate holder was totally secured( much heaver or well staked to the ground) you would have gotten through the 1/2" plate. Plate movement absorbed a lot of energy.

Use the zero on the caliper so you don't have to subtract the thickness of your straight edge. You can also add legs on the straight edge to clear the jagged edges of the hole without grinding.

Probably should have hit the holes with the torch and made sure the lead and jacket weren't still in the hole to measuring depth.

Did roughly the same comparison a few years ago. Using 5.56/AR-15, 7.62x51/ M1A ,7.62x39 SKS and 30-06/ Springfield 1903 . All rounds were FMJ ball ammo, firing at 1/4 and 1/2 in plates @ 100yds. All rds penetrated 1/4 plate, only the 30-06 penetrated the 1/2 in plate.

This guy goes way more in depth with the difference of caliber power than these other gun channels.👍

These videos are quite refreshing in that they are straight to the point with no bull in between. No sponsorships, no skits, or any other such stuff to get in the way while still being interesting and relevant with a decent timeframe. Not that I mind them, but it can get grating after a while. Almost takes me back to the good old days of YouTube prior to 2014. Keep up the good work, you earned yourself a sub and a like.

I agree it came down to bullet composition.

I love that you test these things instead of just theorizing and pointing at box numbers… 7.62x51 isn’t the best for every situation, but you gotta respect how much goes into the development of rounds chosen for military application.

You can see that the bullet geometry is different too. The .308 has a larger flat spot on the nose and you can see the lead on the tip at 6:22 , this helps the bullet mushroom and expend more of it's energy, thus you would expect a wider but shallower hole.

Just found your channel. Really like your evolving test methods (plate rack, grinding away the spalling, adding the spacer to normalize depths, etc). Thanks for producing this concise and useful content!

Really enjoying watching you evolve this process. And these are exactly the kinds of things I've always wished other content creators would do. Keep up the great work!

Good work with the nice tight editing. No temptation to skip anything.

Just found your channel, excellent job. Ex-Canadian military, used the FN when I first joined before the 5.56 conversion. My basic instructors told us while training the standards for the NATO grade where different, and this round would outperform any civilian 308 round.

We were issued with FN Fal rifles during my service (1970's), the ball ammo packages had no reference to spec. details except for the caliber, 7.62x51. The penetration power on various objects/materials was very unexpected and amazing to see. Thanks for your time anf effort on this test.

We were issued with the 7.62 SLR when I joined the NZ Army in the late 1960s. Half inch plate steel was easily penetrated in demos at 100 metres. We were taught that you seek out your enemies who had taken cover by firing through the barriers they hid behind. I think the half inch plate steel was part of the spec.

Glad to see your channel taking off

i love how you did EVERYTHING the way I'd do it! I'll definitely be watching more!