[Mylhouse]

Benton,

First Round Pop (FRP) is a phenomenon common to almost all suppressors. The first shot fired through a suppressor (assuming it hasn't been fired in a while) is louder (but not always) than subsequent shots. The reason? Before the first shot, the can is full of oxygen. When you fire that first shot, the flash and combustion gasses of that shot consume the oxygen present in the can, making the suppressed shot louder and the flash coming out of the can brighter (than if the can was devoid of oxygen before the shot). The following shots will be quieter because there is less oxygen after the first shot. There are various ways to sidestep this issue (artificial medium [water or grease], blast of CO2 spray into the can prior to the shot, etc).

DW,

The AAC can would be a smart way to go. If I were to pick a can to go with, it would be the 9mm Omega GSG-9 can made by SWR Tactical. Given your parameters, I would go with a HK Tactical .45 and some sort of single shot or bolt .45acp or .45Colt (if the bullet passage of the can allows enough room). If you don't like recoil boosters (Nielsen devices), then you can forget using a Glock or 1911. Seriously, go with the HK Tactical. It is a dang fine weapon.