How do I unlock the "SPECACT" (special action) weapons in battlefield bad company 2? Also, how do I unlock the M1 Garand?

I have all of the over weapons/gadgets unlocked except the SPECACT weapons and the WW2 M1 rifle.

What is the difference between the SPECACT weapons and their regular counterparts? Are they more accurate or cause more damage than the normal weapons?

This is really bugging me.