Just becuase the back end of a target isn't all blown out like a .30 rifle round just does not mean there is a clean .30 cal hole through and through. A round going that fast (Specially at smg velocities around 2200fps) it's going to leave a CONSIDERABLE wound channel through soft tissue, not to mention extreme fragmentation of bone if one was in its path.
At least from an SMG you're talking very similar muzzle energies to 5.56 in a 16" carbine.
The 7.62x25 is defitely pretty close to the top of the list of "pistol" rounds I wouldn't want to get hit with. Reguardless of any old wartime addadges based off the superficial appearance of a wound.
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