The AK-47 shoots a 7.62 x 39mm bullet. The 39mm indicated the length of the brass/steel case.
7.62x39
The AK-47 uses the 7.62x39mm round. Note that the AK-74, a similar firearm uses the different 5.45x29mm round.
The AK-47 and AKM use the 7.62x39 cartridge.
7.62x39mm
7.62mm bullet More specifically a 7.62x39mm bullet (the military version of the .308 winchester).
36countries use Ak-47?
The term "762" refers to a 7.62mm bullet. This is a common size for European guns and the AK-47. The 54 refers to the length of the round or the powder, I forget. Not sure exactly what bullet this describes but that is the diameter size (caliber) of the bullet.
Best left to a gunsmith
Very small trees.
one hundred and twenty three pounds
In the 2000-2200 fps range.