I just hope the OP who ask the question is trying to find a round to minimize penetration.
Minimizing penetration is the worst thing you can do in a home defense scenerio. I don't know where all this hype behind over penetration came from, but if you'll note that professionals don't buy it and still adher to minimum penetration standards rather than maximum penetration standards, then you can understand that penetration is your friend. Too much penetration can be dangerous, true. But not enough will get you killed, and it is far easier to get too little penetration than too much.
The FBI requires at least 12 inches of penetration, even after penetrating heavy clothing, rolled steel, or windshield auto glass. You think they do this because they want minimum penetration? Or because they have lost agents do to just that and set protocols to avoid it in the future? They as well as myself both like 14 to 16 inches rather than just 12.
The bullet must be able to reach the vitals regardless of what shot angle, muscle or bone tissue, or other obstacles it encounters.
When you consider the majority of Americans are overweight and 1/3 of them are obese, why would you work to minimize penetration? Because some mall ninja who has never shot living things with a gun recommends varmint bullets in a .223 or birdshot in a shotgun?
I have shot living things with these loads, and while impressive on small game, they were obviously not ever intended to be used on larger, more dangerous game, such as humans. Some people must be able to guarantee that the bad guy in their living room will be one of the ones that isn't overweight, and that shot presentation will be the ideal frontal shot as on the range, and that the bullet won't be required to penetrate a forearm, heavy clothing, and several inches of fat tissue, muscle, and bone before
entering the chest cavity and
beginning its job. I, however, can make none of these guarantees, so I load to get enough penetration on big guys, even with less than ideal shot presentation.
In 7.62x39, any M67 pattern ball round will work, even if not ideal. My experience shows the 122 gr Wolf FMJ has an air pocket in the forward 1/3 length of its nose to induce rapid yawing. In gelatin, this bullet typically begins yawing within the first 4 to 6 inches of tissue, verses 8+ inches in the original M43 ball round. My single experience with this bullet on game was a broadside shot at a small (~140 pounds live weight) white tail doe from about 50 yards. The bullet entered behind the onside shoulder and exited through the offside scapula sideways, leaving an oblong exit wound with scattered bone fragments and other nastiness. The doe made it 40 to 50 feet, curled up under a tree, and died. My limited experience shows this load to actually do more damage than a .223 caliber 55 gr Winchester soft point at the same range. The bullet will, nevertheless, still penetrate 14+ inches of pine and still be lethal. So as with everything else, misses will be a lot more dangerous to bystanders than those that hit the bad guy.
The Wolf 122 gr JHP, in my experience, fragments rapidly in water. I've never shot anything larger than a ground squirrel with them. When I have the choice, I keep JHPs in my AK for self defense rather than FMJs, but I've had them both loaded next to the head of my bed at one point or another. As the testing results posted by another poster indicate, most of these loads still penetrate 12+ inches in gelatin, but anything that manages to exit the body will more than likely lack sufficient energy to penetrate several interior walls or exit the building. This can not be said to the same degree about the FMJ, which even sideways or traveling base forward, could possibly still be lethal or penetrate a couple walls.
I'll probably switch over to the Wolf MC 124 gr JHP for defense from now on...
