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Old October 13, 2002, 09:56 PM   #1
hso
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7.62x39 limits

Can 7.62x39 be loaded to come close to 7.62 NATO performance from a 20in. AR upper?

If so, where can I find this information?

What needs to be added to the upper to make it safe to shoot such a round?

Thanks.

Mike
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Old October 14, 2002, 12:40 AM   #2
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Best I can tell, max loads...

...for 7.62x39 are pushing 130gr bullets at 2200ish fps, which is a fair piece off .308 numbers.
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Old October 14, 2002, 12:52 AM   #3
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Quote:
Can 7.62x39 be loaded to come close to 7.62 NATO performance from a 20in. AR upper?
NO
Neither safely nor unsafely.

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Old October 14, 2002, 02:58 AM   #4
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Not only "no", but "hell no".
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Old October 14, 2002, 09:53 AM   #5
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Tam, et al, I was wondering if Breed could get similar performance to the 7.62 NATO from a tweaked Sov. 7.62X39 in the corresponding 20 in. AR upper.

Oh well, so much for that idea.
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Old October 14, 2002, 11:21 AM   #6
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The case is just too small. The cartridge already does what it can with full cases of fast burning powders. There's just no room for extra performance.
A more entertaining niche for the short Russian is converting it into a heavy bullet subsonic cartridge for use in supressed uppers.
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Old October 14, 2002, 02:46 PM   #7
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Given the same bullet weight, not a chance.

A more entertaining goal is to attempt to achieve .30-30 velocities with a given bullet weight.

But why play with a new velocity, which will throw off your sights for factory ammo? I like to pick a good factory ammunition, and duplicate it, but with higher accuracy and lower cost.

Considering how cheap 7.62X39 is and how inaccurate my SKS is, reloading jus ain't practical for it; there's no payoff.
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Old October 14, 2002, 07:27 PM   #8
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Poodleshooter,

This would be the Whisper in 7.62 approach? Could this be done with a heavier bullet to offset the momentum down to subsonic velocities?
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Old October 15, 2002, 11:02 AM   #9
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It has been done. Check with Kurt from Kurt's custom on the www.ar15.com board if he's still there. I'm not sure if he posts here, but I seem to recall that he did work with it. Probably other's as well. You can check the gunsnet AK board for other archived info. Usually the format is to reload using a .308 expander ball instead of a .311, and to then use a 240gr SMK boosted to around 1000fps. In theory it makes a heck of a lot more sense, as finding .221 fireball brass to make Whispers is probably more expensive than using 7.62x39. I haven't tried it because
A. 240gr SMK cost money
B. I'd rather not blow up my AK
C. The twist rate would be VERY different for stabilization out to 100yds. You're going from a rifle designed to shoot 123gr bullets at 2300fps to one shooting a much longer 240gr @ 1000fps. You need a MUCH tighter twist. Shooting it out of a stock AK/SKS/7.62 AR will give you a nice keyhole at 100yds. Custom barrels are a must.
D. I don't have a silencer, nor do I wish to seek the Fed's approval to own one. Sans silencer, the project is much less interesting
E. I don't need one. I like cartridges that make loud noises. If I ever silence a round, it will be a nice slow pistol cartridge.
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Old October 15, 2002, 11:30 AM   #10
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Check out the Knob Creek thread on the General board - A guy who was partying with us had a TC Contender that he'd chambered for a .50 cal wildcat made from shortened .50-90 brass, with a .50BMG bullet. He said it ran about 900 fps. 700 grains packs a LOT more thump than a 240 grainer...
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Old October 15, 2002, 02:23 PM   #11
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Kind of a bit off topic, but pretains to the 7.62x39, particularly in an AK. Theres just no way to get .308 velocity from a 7.62x39. Not that Im aware of. But I have been playing with the 7.62x39 lately for my AK. We all know how much fun tracers can be at dusk. Wideners has a special on USGI pulled 145 gr .30 cal tracers, 3000 for $115.00 or so. I originally bought these with the intent of loading them in .308 and .30-06. Then I found the RCBS 7.62x39 dies with .308 and .310 expanders, and the wheels started turning. According to the US Army load data manual, WCC-846 was used to load .308 tracers. WCC-846 cross refences to BLC-(2). I am currently working on a tracer load for my 7,62x39 AK using these 145gr .308 tracers and the WCC-846, Using BLC2 data for 145gr bullets. The loose tolerances of the AK allow a .308 bullet to be used, and many have done it to use heavier bullets. The only variable is wether or not I can get enough powder in the case to light the tracer safely. However, after I came up with this idea, one of the ammo dealers at a local show was selling some brass case 7.62x39 (R-P) with orange tracer heads. He had it marked high of course. I havent gotten any loaded yet, but I'm almost there... Wondering if anyone else has done this before me.
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Old October 15, 2002, 03:13 PM   #12
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I've tried WC846 with 123gr SP, and was unable to exceed 2150fps even with highly compressed loads. It's just too slow. tracers might be even worse, as they are usually quite voluminous per unit of weight (the tracing compound weighs less than an equivalent space of lead or steel).
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Old October 15, 2002, 04:21 PM   #13
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846, 844. 844 crosses to H335. Then thers 4895 to try as well.
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Old October 15, 2002, 05:50 PM   #14
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The HOTTEST 7,62X39 load I've ever seen is 26,5 grains of Vihtavuori N120 powder, SAKO 123grs FMJ-bullet, LAPUA 7,62X39 case and Vihtavuori No.68 primers (C.O.L 2,293").
Velocity is 2430fps out of a 16,5" barrel.
Pressure is 45.000psi and this is the SAAMI max. pressure!
I found this load in the Vihtavuori Reloading Manual second edition.

It is ABSOLUTELY IMPOSSIBLE to load the 7,62X39 to the same level of the .308 Win!!!

Try this and you will experience the disintegration of your rifle and most likely you'll miss some of your body parts afterwards.

DON'T DO IT OR YOU'LL REGRET IT!!!
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Old October 15, 2002, 07:38 PM   #15
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I thought max SAMMI was 50,000 on the 7.62x39?

Either way, the goal should be .30-.30 balistics, not .308.

As for me? I just want my tracers to light. Speed isnt a concern. Slow tracers are cool. Im going to start with published Hogdon load data for BLC2 under 150 gr. bullets, and reduce by 10%, maybe more. I THINK the data on their website is MAX loads. Looks to be anyway. My tracers are 145 gr.
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Old October 15, 2002, 11:12 PM   #16
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@ Krautguns:

According to the VV Reloading Manual, Max. pressure for the 7,62X39 is 50.000 CUP or 45.000 psi.
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