5.56x45 or 7.62x39?

[481]

I assume those P[I/H] & T[I/H] figures change when barriers are introduced? I don't necessarily mean a car door or wall, but heavy clothing too.

I'm not discounting the capabilities of 5.56, but anecdotal evidence of some Vietnam vets (including at least one on this forum) are the 7.62x39 was pretty devastating.

Through 2-layer and 6-layer uniforms, the effect is negligible.

Harder, more durable barriers, like car doors, automotive glass, and construction materials introduce significant effects that diminish both P[I/H] and T[I/H].

 

[BreechFace]

M16


From what Ive seen current production M855A1 averages about 3125 FPS in a 20 inch barrel and 2950 FPS in a 14.5 inch barrel. I'd guess you would hit around 3000 FPS in a 16 inch barrel. In testing it was hotter and was causing premature wear on the rifle, but it seems like they tamed it down a bit for full release.

M855A1 is not a FMJ though. From what Ive heard from buddies that are still in or recently got out of the Army, it works really well.

Those are the velocities I'm seeing as well for the M855A1 and like you I've heard great things about this round, a big improvement over M855.

 

[481]

@481 So M855A1 gains another 100fps over M855? Most M855, 62gr hovers right at 3,000fps from a 16" barrel, from a 20" barrel one sees 3,100. Just my experiences and research.

I have no experience with M855A1, so if they got another 100fps that's a definite step up from the M855 along with the projectile benefits.

I know it's not a huge deal, but it's good to keep things consistent.

It really isn't a big deal.

I've run the 1968 BRL P[I/H] and T[I/H] models using muzzle velocities of 3,100 fps and 3,000 fps for the M855A1 against the M67 for your edification...

M855A1 with a muzzle velocity of 3,000 fps—



M855A1 with a muzzle velocity 3,100 fps—

Still the same result; out to 50m, the 7.62x39 M67 is the superior choice, but it still loses out to the 5.56x45 M855A1 all the way out to 300m.

BC for M855A1 is 0.291, BC for M67 is 0.225

 

[Goosey]

Okay, so let's discuss the images here. This is "resin"? How does that compare to 10% ballistic gel, or to the human body?

Soap or resin just captures the temporary cavity... in that medium.

10% ballistic gel:



And if we make the comparison a bit clearer by only showing the permanent cavity, and stopping at 18" (FBI overpenetration)




The 5.56 is going to be better WITH FMJ because it's going 400-800 fps faster and will more easily fragment its FMJs. Beyond the fragmentation threshold you have a better battle, but the fact a fragmentation threshold exists at all makes 5.56 FMJ the king of this comparison.

I'm thinking of M193 and M855, but I wonder if M855A1 also counts as a FMJ for the purposes of this question. Some people are talking about the 7.62x39 8M3 and such... 8M3 is not a FMJ, it's a hollow point, which is straying off-topic.

 

[drobs]

I still need to kill a deer with a 7.62x39 SP / HP maybe next year. I will be using Federal Fusion 7.62x39 hunting ammo.

I have a few AKM's in 7.62x39. I personally built the 2 on the left and 2 on the right from Romanian G kits. I no longer own the Polish Tantal 5.45x39.

The AK on the far right will shoot 2 inches at 100yds from the bench.

My only AK style 223 / 5.56x45 is my Galil:

I've killed 2 deer with my Windham AR15 and 62gr Federal Fusion 223. Both were shot under 200yds:

2022

2019

I see lots of folks use 7.62x39 on hogs. Being an invasive species in most states, I'd bet a lot of them are killed with FMJ.

https://texashuntingforum.com/forum/ubbthreads.php/topics/4081554/7.62_X_39_Tula_Ammo_(FMJ)_Good

 

[d2wing]

I have used Federal Fusion Sp, in both 7.62x39 and .223 on deer. Shoot them in the heart and they are going to die quickly. The difference is that the .223 gives you more range and does a great deal more damage to tissue like lungs and everything else in the chest cavity. It only makes a difference if you just get a lung shot. Much more internal blood loss with the .223. It turns the lungs to mush. Shot placement is the key no matter which you use. I prefer the AR for much great accuracy and tissue damage, but a higher power bolt action over both. I have killed pretty big Minnesota bucks with both. Those formulas are mostly BS. I have more faith in results in flesh than Jello as well. FMJ are illegal for hunting where I live so that discussion is moot for me.

 

[481]

The BRL energy-based (ΔE15) provisional incapacitation formulas were used by the US military to develop a cartridge, the 5.56x45 M193, that matched the terminal performance of the Soviet 7.62x39 M43 (encountered by our soldiers during the Viet Nam war) while allowing a greater amount of ammunition to be carried by our soldiers into the field. The reported experiences of soldiers in the field (including one THR member earlier in this thread) confirms that the reality and the theory (the BRL formulas) match one another.

If the formulas match reality, then the formulas are valid. History has shown this to be a fact.

 

[Beck]

Beck (or whoever might know):
As for fellow new NATO member Sweden, doesn’t Sweden have many thousands of G3 rifles stored in mint condition ? A poster stated this on a different gun website.

If they no longer use the A4 (Swedish model) G3, maybe they could Donate them to Finland for a better effective range in open areas.

I would not worry about Finland. They have military capability greater than Germany and France combined. Having a border with Russia that stretches over 800 miles, they have to. By the way... Welcome to NATO, Finland! It's official!

Other than their standard issue RK 62 in 7.62x39, they have "Squad Designated Marksman Rifles" in many configurations just like the US and other modern militaries. Those include the Russian Dragunov in 7.62x54r and many weapons of their own design chambered in 7.62 NATO, among others. Finland provides specialized weapon systems to other countries, including The US and Israel.

My point was, why would such a capable military choose a weapon chambered in 7.62x39 as their standard issue? It's something to think about when answering the OP's original question.

The answer is not a difficult one for me. I know and love the cartridge. Been using it since the 1980s. My introduction goes back to when I was a teenager working at an auto parts store for a Vietnam vet. He had an SKS... a war trophy that he dearly loved. That was the first firearm chambered in x39 I handled.

It would be many years later I would have my own carbine in 7.62x39, a 189 Series Ruger Mini-30. I've had it for over 33 years. I've been handloading 7.62x39 for the last few years. I know how capable the cartridge is. 300 yards as specified by the OP of this thread is easy.

The 7.62x39 cartridge is not stuck in 1943, or 1967. It's been improved like most other cartridges. Finnish made 7.62x39 is considered the Gold Standard by many.
Finland's Lapua provided the proof cartridges for the Mini-30 and assisted Ruger in establishing the SAAMI standard for the cartridge. Before the Mini-30 was in development there was no SAAMI standard for 7.62x39.

Finland's Sako and Lapua, in cooperation with Britian's Accuracy International, developed the 338 Lapua Magnum, which is used by US navy SEALs among many others. Finland champers 338 Lapua Magnum in their own TRG-42 sniper rifle made by SAKO.

Well, like I said, Finland could chamber their standard issue battle carbine in any caliber they want, and they do chamber the RK 62 in several other calibers. But they chose 7.62x39 as their main standard issue. So did I!

 

[d2wing]

The BRL energy-based (ΔE15) provisional incapacitation formulas were used by the US military to develop a cartridge, the 5.56x45 M193, that matched the terminal performance of the Soviet 7.62x39 M43 (encountered by our soldiers during the Viet Nam war) while allowing a greater amount of ammunition to be carried by our soldiers into the field. The reported experiences of soldiers in the field (including one THR member earlier in this thread) confirms that the reality and the theory (the BRL formulas) match one another.

If the formulas match reality, then the formulas are valid. History has shown this to be a fact.

I am also a Vietnam Vet. A combat vet. So don't pull that stupid crap on me. That the 5.56 is more effective was proven then and has been proven for 50 years in combat results. You can read all the BS you want. Yes history has proved the fact that the 5.56 is more lethal than the 7.62x39 and always has been. Further proof is that the worlds largest militaries have developed versions of the 5.56. Of course all the NATO countries use it too. Not that it matters to me. I know what I know first hand.
There is no point in arguments about this because for everything I say you have a counter to suit your bias just like the guy that started this thread. Everybody is just looking to support their bias. My opinion is based on real results. I don't need any input from anyone else. In my opinion nobody is going to listen and everybody is going to keep the bias they have. That half think the 7.62x39 is better proves that BS and bias carries as much or more weight as facts.

 

[Robert]

8 pages seems like more than enough for a caliber war. As always, use what you like and allow others to do the same.