7.62x39, really big and really small

[R.W.Dale]

First, remember that the AK/SKSs all work at ~40,000. Your CZ doesn't have the strength of a large ring Mauser, but it'll certainly beat out the AK. Are you measureing the case head diameter (ala Ken Waters' method of pressure watching)?

Recently It's been pretty well proven that the old case head measurment methiod of pressure estimation is pretty well worthless, as well as primer appearance.

But you'ed have to have some pretty hot 7.62x39 loads to get outside of the pressure range the CZ527 is rated for. .221 fireball and .223 being pretty intense cartriges pressure wise.

 

[Cosmoline]

I'm very impressed with the CZ's action. I have a feeling I could load it up to 60,000 or more and it wouldn't be a problem. But I doubt it's even possible to reach those ranges with the powder and bullet combinations I'm using for the large loads. The Unique loads actually pose more of a risk

 

[gringobaba]

Cosmoline - Any updates?

Anyone ever try .32 cal. pistol bullets?

 

[Cosmoline]

The S-10 has cracked heads, so I ain't goin' nowhere for awhile. I may be able to get over to the range later this week with a borrowed ride. But I suspect a .308" bullet in that weight range will end up working best.

 

[Cosmoline]

OK, I slipped down there today in spite of the cracked heads. The load I used was 23 grains of the IMR 4198 under the Speer .311" 180 grain RN's. This gave me 2,050 FPS on average and is about as hot as I care to go. I could probably squeeze a bit more powder in there since I'm not actually at the limit of the magazine's OAL capacity. But I like it right where it is. Accuracy with these .311" bullets was MUCH better than with the .312 high-ogive woodleighs. I got a single half inch hole just below point of aim at 25 yards and a nice 2" group at 75 with iron sights in very bad glare. I'm confident that could be cut down smaller with better light conditions or a scope.

The ft. lbs. on this load are about 1680 on average. Not exactly magnum-levels, but those 180's have a sectional density of .266. This would be a perfectly acceptable round for large black bear, hogs, large deer or moose for inside 100 yards. Not sure about elk, as I have no experience with them. No, it's not going to get you into .30'06 power levels, but the carbine in question is a 5 1/2 pounder that totes like a handgun. Recoil even with the maximum load is minimal.

Unlike Woodleigh, Speer doesn't list the specific range of ideal velocities at impact. However, Speer says these Hot-Cor styles "promote reliable expansion even at lower velocities." So I should be good as long as I don't push the range.

So that's the end of that experiment for now. I think I've at least proven that the 7.62x39 can indeed be loaded to match the .30-30 with heavy bullets. But I'd only suggest trying this sort of thing in a mini-Mauser or Ruger M-77. I would NOT advise it in the Mini-30, SKS or AK-47. I have no idea what these loads would do to the gas systems in those rifles.

The wee loads should be fine, as well, but I wouldn't go below 7 of Unique due to spike possibilities. And I don't want to risk a ringed barrel by packing dacron filler in a bottleneck case!

One thought--there was little excess flash with this load in spite of the very short barrel and large powder charge. The IMR 4198 seems to use its steam up in the short barrel. This might be of note to .30-30 handloaders who like to use the little spikehorn style carbines. One problem with those is the velocity loss and excess f&b you get with standard .30-30 ammunition. If you used 4198 instead of 3031 (with appropriate reduction in charge amount) you might be able to work up a very good spikehorn load.

 

[only1asterisk]

The load sounds almost perfect, you may play around with the seating depth and see if you can't tighten it up a touch. I think the Speer bullet should be ok down to about 1800fps and maybe a bit below. With this load I'd keep using the iron sights and pass on shots over about 100 yards.

David

 

[jjohnson]

Ballistics Programs Sanity (Safety) Check

I second OneAsterisk's suggestion to let somebody who has a decent ballistics program like QuickLoad check this thing out for you - nobody can make any guarantees, and the lawyers might have a fit over the idea, but when you're loading "outside the box" running the data through a ballistics program is an idea with real merit. Most of us would rather laugh at your post if you wind up having to beat a stuck bullet out of a barrel from a squib load for underloading than to read your obituary after you loaded something too hot. Handloading's exciting, but it doesn't have to be THAT exciting, eh?

Do be sure and post your results - I handload 7.62 x 39, too, and have a bolt action with a .308 bore (as well as sks) so I play with things like 150gr cast for plinking.... not limited to loads that'll routinely work well in an SKS, so I'm interested in seeing how things go. Please do take the safety idea seriously.

 

[Cosmoline]

That's why I waited till I had a '98 pattern to try the experiment. The powder/bullet combo is likely to put pressure at the maximum range and be far too great for most gas systems. But there were no signs at all in the CZ. Without a test barrel there's no way to tell exactly what the pressure is, but I wouldn't worry about putting this through any Mauser-based action.