Robocop had it right. During WWII the OSS used silenced rounds in .30 caliber. That round uses a captured piston to propel the bullet. It was subsonic. Got one somewhere in my junk. Will try to find it.
BTW: There is a silenced HE Frag round for the 40mm M203 and M79 grenade launchers.
BTW: There is a silenced HE Frag round for the 40mm M203 and M79 grenade launchers.