The trick to not mess up your powers of 10 when doing metric is to start in kg/m/s, once you remember that, you can stop worrying.
Incidentally, the symbol for Newton is N, not nt.
Bullet 1 has a mass of 4*10-3 kg and a speed of 1000 m/s with a surface area of 0.25*10-4m2. (M-16)
Bullet 2 has a mass of 25*10-3 kg and a speed of 400 m/s with a surface area of 1*10-4m2 (.45-70)
For deceleration, we've been using an ideal material which regardless of deformation and velocity applies a constant pressure on the surface of the projectile of 10N/cm2=1*105Nm-2 (very low incidentally, it's equal to the atmospheric pressure)
This gives deceleration forces of
This gives deceleration of
This means, following d=½v2/a, that penetration in this hypothetical material will be:
Reductionist and proud of it.
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