Silencer FAQ

"First round pop" (FRP) refers to the slightly higher level of noise that you'll hear from your suppressor on the very first round you fire through it. FRP occurs mainly because of the oxygen that is inside the suppressor when the first shot is fired. The oxygen allows the powder that is propelling the bullet to continue to burn through its explosive cycle to maturity. The suppressor will trap much of the gasses produced in the first shot, which results in an oxygen deprived environment that will help control and shorten the explosive cycle of subsequent rounds.

A booster, or "Nielsen device" is a mechanical device located at the rear of most handgun suppressors. Its purpose is to ensure that semi-auto handguns will properly cycle the next round after firing. Without a booster, most sem-auto's will have difficulty feeding the next round into the chamber. Malfunctions (failure to eject, stove pipe, failure to feed, etc.) occur because the extra weight/mass at the end of the barrel will slow/impede its movement as it travels out of battery. The booster helps overcome the suppressor's added weight on the barrel by using the explosive blast (as the bullet clears the end of the barrel) to help push the barrel backwards, out of battery (see animation below).