Suggestions for lead cast loads in 7.62x39

I don't think you will like the results shooting 2000fps without gas checks. I predict leading, possibly severe.
A 125 to 150 grain gas check will probably do you fine. I know its a pain and one more step and more expense but it is worth it.
I've shot some plain base bullets, actually a lot of them in 40-40, 308, 30-06, 30-40, and 7.7 along with 45-70 and the only one that worked well was the 45-70 and that was a black powder load probably not hitting 1300 fps.
Plain base, hard cast bullets with Trail Boss at around 1300-1500 work pretty well.

I experimented with some cast lead bullets from Hunters Supply in an SKS. They were BHN 15, and rated to 1,600 fps without a gas check. They were 115 grain @
.313 diameter. I applied a coating of Lee Liquid Alox to them.

To stay around 1,600 fps I tried a load 8.5 grains of Unique. It clocked 1,615 fps on my chronograph, but didn't cycle the action!

Then I tried a load of 17.0 grains of IMR 4227. It cycled the action and clocked 1,651 fps on my chronograph.

This was three years ago and I can't find any records of group sizes in my file. Maybe it didn't do very well!? I don't remember.

Lead for AK? Skip it.

I had a Saiga and wanted to reload for it, using the Lee 155gr gas checked mold. It chrono'ed around 2000 fps, and right around the 70 round mark the action locked solid.

A ring of lead formed in the gas cylinder, locking up the piston. It took a mallet to free it. Not only that but finding reloadable brass was a real PITA and chasing that stuff all over the range was the last straw.

I had enough and traded it for an AR.

Interestingly I've discovered the secret to using a gas checked 180gr in my Garand. Go figure.

At a bare minimum, use jacketed, plated or powdercoated bullets and use a brass catcher.

Lead bullets in gas operated guns are a recipe for failure

Small bits of lead will be shaved off by the gas port and will eventually lock it up

I would not use Lead in a gas action, plated would be a option if the people that make them would get a clue they say don't run them more than X fps, which means I may not cycle the action. So why not make a 150gr .311 dia. plated bullet so I can have my cake and eat it to They pull the the same crap for the 30-30 Win I can't find a 170gr plated bullet.

Lead bullets in gas operated guns are a recipe for failure

Small bits of lead will be shaved off by the gas port and will eventually lock it up

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My SOCOM would disagree. I've fired upwards of 20 magazines at a sitting, and its never stopped once from a gas tube obstruction.

Now, the guys who drive soft alloy bullets way too fast ? I can see that.

I had a Saiga and wanted to reload for it, using the Lee 155gr gas checked mold. It chrono'ed around 2000 fps,

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That seems like a good example. If you're going to be running un-checked lead in rifles at that speed, I'd be hesitant to start at less than 22BHN. Heck I run north of 22BHN WITH gas checks for rifle. Stripping out the rifling in fast twist rifle barrels is a recipe for disaster in a gas operated system.

I've also seen/felt many gas assemblies/barrels that were mighty rough at the gas port, and this would just make the situation worse.


With that said, im still looking forward to trying powdercoated rounds this summer, as occasionally too much bullet lube will build up at the end of the chamber, necessitating a range time scrubout for proper chambering.



Back to the OP :

I would suggest the heavier 150 gr mould, and I would use straight linotype or its equivalent.

As to a powder ? H4895 downloads well, while still providing necessary gas volume to cycle a gas-auto. The .1/.2 possible variance you'll see using it in a powder drop won't be noticed on paper with the weapon/projectile combo you're going to be using.

I'd also try powdercoated rounds, if you could. I'm going to be testing the 150 in 7.62*39 this summer ( hand willing ), maybe we can compare notes !

Harder alloy is not always the answer and sometimes part of the problem.

I'll try just about anything at least once, and that includes cast bullets. I've never actually gotten hold of any but some of the thin-jacketed varmint bullets I shoot are pretty soft, and they give me a good idea of what I would be up against with true cast bullets if I were to ever get them. Soft bullets are a challenge because they deform readily and quickly foul the barrel. They seem to do better in a long barrel with a slow powder that can slowly push them up to speed without deforming them too much. This probably explains the "long guns" of yore, when shooters were typically casting their own bullets. The idea seems to be to be to keep the pressure low enough so that a cushion of gases is cupped around the projectile as it travels forward through the barrel. I've found that when I get close to overcoming that cushion and plugging the bore, projectile speed begins to rise disproportionally to the increase in powder charge. Indeed, stopping just short of full obturation with soft bullets is a real trick and seems to require extremely consistent reloads.

Could you please elaborate on this? Specifically, what is 22bhn? Also, what would be considered too fast of a twist?

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BHN : Brinnel Hardness. The hardness of the alloy used to make the bullet.

Whats too fast ? Thats going to depend on a variety of factors. In .224, the 1 in 7 twists tend to rip softer alloy bullets right out the rifling every time. Its easy to see how much lead you are losing to rifle stripping by examining your muzzle brake/flash hider if you have one; the excess lead will be nicely deposited in a twisting arc all over the brake. With 1 in 10 ( 1 in 9.75, actually) I don't think you'll encounter this problem in an AK variant with a stock barrel but its important to note for a lot of the other gas-auto shooters out there looking to give this a go.

Thanks for the recommendation.

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NO PROBLEM.

With that AK, nice thing is during your testing accessing the gas port area is much easier than on an AR variant. Simply pop the tube every mag during your testing runs to evaluate the buildup of residue at the top of the gas system. You wont get right to the barrel/port area, but the cleanliness or dirtiness of that area where it bends back to the direction of the receiver will give you a great indicator of whats going on at the port !