In reply to some of the comments, the web is full of good info on 7.62x39 and it's capability... far hotter with much more potential than domestic factory loads adhering to SAAMI. And I wouldn't worry about the so-called Russian ammo ban. It hasn't gone into effect and likely never will. If it does it'll be short lived. All ammo in most calibers is more expensive these days and harder to find at reasonable prices, when you can find it at all.
Ruger established SAAMI pressure standards for 7.62x39 with assistance from Lapua, Finland, and they completely botched it through miscommunication. It should have been corrected long ago, but apparently there's no real incentive. Instead people keep trying to recreate 7.62x39 and call it something else. 300 Blackout and 300 Ham'r are the most recent x39 inspired that come to mind.
x39 factory ammo made to European C.I.P. standards is generally hotter by as much as 200 to 300 fps than many US domestic factory loads with the same weight projectiles. And with handloads the sky is the limit.
My 32-year love affair with x39 has given me plenty of insight, experientially and through research. I don't want to hijack this thread with the pages of info I could share, so at some point I'll start a new thread on x39.
Back to 300 Ham'r... it's been called a rimless 30-30 by Wilson, and that's pretty accurate, but that can be said of x39 as well. Both 300 Ham'r and x39 have the advantage of using spire point bullets with much higher BC in semi-autos. x39 has an added advantage of loading subsonic, same as 300 BLK.
Wilson's description of 300 Ham'r is eerily similar to early Ruger ads for the Mini-30 from the late 1980s... almost verbatim. The difference is Ruger was drastically underestimating x39 when comparing it to 30-30 in those early ads pitching the Mini-30 as a deer rifle. That's another story for another thread.
One more thing about 7.62x39. It's not limited by physics, but by philosophy. A shift in philosophy after WWII of new warfare for small arms, which was basically the least amount of powder and projectile to get the job done. Some people are still stuck in the past when it comes to the potential of x39. Others have discovered how much more it can do with modern powders than it was originally intended to do.
I'll stop there for now. No one has ever accused me of being concise.
~ Beck