In "The Return of the 8M3 Effect Bullet" at the The Firearms Blog, the author notes:
There are a great number of “hollow point” loads available in 7.62x39mm from the various Russian brands but, with very few exceptions, these projectiles behave exactly like full metal jacket in tissue. There are a few American loads that have excellent terminal performance, but these are far more expensive.There are Russian 124 gr and 154 gr soft points available, and these do generally tend to expand well, but they are not reliable and some users have reported feeding problems with soft points. What’s worse, Russian ammo makers seem to change components more often than Bruce Jenner changes his mind. You never really know what projectile will be loaded in the ammunition you buy, unless it is actually labeled with the specific projectile design, like Western ammo.
Unfortunately, as the author relates, the 8M3 ammunition has not been imported into the United States for some time. However, he reports that Tula has begun importing 124 grain hollow-point (HP) marked as 8M3. Testing seems to confirm that it is the genuine thing:That’s where the 8M3 “effect” bullet from Ulyanovsk comes in. Loads made using this hollow point bullet with internal scoring on the jacket developed a formidable reputation for brutal terminal performance.
Approximately 2,400 fps velocity with an ideal penetration depth of 14.7 inches. This meets the FBI recommended minimum of 12″ without exceeding the max recommendation. Right in that Goldilocks spot. The disruption produced is astounding and leaves nothing to be desired with extensive fragmentation, but the size of the fragments are of a size that is large enough to cause significant wounding. The neck, that is the distance the bullet travels before starting to yaw, fragment, or expand, is so short that it is barely measurable.