The force of the rifle on the bullet and the force of the bullet on the rifle are equal in magnitude but opposite in direction, according to Newton's third law of motion. However, the mass of the rifle is much larger than the mass of the bullet, so the acceleration of the rifle is much smaller compared to the acceleration of the bullet.
7.62x39mm
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 shoots a 7.62 x 39mm bullet. The 39mm indicated the length of the brass/steel case.
If by flip you mean tumble in the air then it depends on the type of AK that is being fired. If the AK is cheaply made and has a low quality barrel then the bullet may tumble in the air. Quality AK47s do not have this problem.
7.62×39mm
The bullet energy from the AK 47 is higher than a round from an M16 or M4. That doesn't mean it is necessarily a better weapon. The AK 47 is very reliable but the M16 is much more accurate.
In the 2000-2200 fps range.
1776mph over 2000fps
one hundred and twenty three pounds
Best left to a gunsmith