The Russians simply took their old rifle round and shortened it. Coming up with this new intermediate rifle cartridge was to help lighten the load on a soldier carrying the new SKS carbine and reduce the recoil. Most, if not all, 7.62mm Soviet cartridges are Berdan primed.
Different variants of the 7.62×39mm round.
The M43 round, with its 124 grain full metal jacket bullet has a muzzle energy of 2010 J when traveling at 715 meters (about 2300 ft) per second. It has a mild steel insert on the inside of the bullet, with a layer of lead beneath the copper-plated steel jacket. However, it is one of the poorest performers in terms of terminal performance; its deep penetration, while working very well against cover, does little damage on flesh unless it hits a part of the central nervous system.
The M67 round, produced by Yugoslavia in the 1960s, does not have the mild steel insert that M43 has. This causes the projectile to have a center of gravity that is not in the center of the projectile while in flight, increasing its chances of yawing upon impact and producing a larger wound than M43 would.
Commercial manufacturers of 7.62×39mm generally have various FMJ rounds on the market. Most weigh around 122-124 grains, and are generally steel-cased and Berdan primed.
Modified M67 with a ballistic tip, increasing chance of fragmentation.
158-grain 7.62mm Soviet
These are usually jacketed hollow point rounds. Effectiveness of the hollow point design may vary, and are usually sold under the Herter's brand.