They should equip themselves after the mission in which you obtain them- or try equipping the gun and then equipping the silencer while the gun is already equipped. Hope this helps, lemme know... zero_of_stoikos - 8 years ago
you only get silencers on certain weapons, such as the MK 22. the MAC10, and the assault rifle that resembles an M4.
they start out with a silencer equiped, if it's used up, that's it, no more silencer untill you either restart or go to the next mission area. riddlebox89 - 7 years ago
This question was asked more than 60 days ago with no accepted answer.