Recoil booster for firearm sound suppressors

A recoil booster for use with a sound suppressor for a firearm, comprising:

• a hollow piston having a head portion at a forward end defining a first outer periphery and an elongate generally cylindrical portion rearward of the head portion defining a second outer periphery, the piston configured to be coupled at a rearward end to a barrel of the firearm;
• a cap assembly including a forward portion having a first inner periphery configured to slidably guide the first outer periphery of the head portion of the piston and further configured to be spaced from the second outer periphery of the cylindrical portion of the piston to define an annular space there between, the cap assembly also including a rear portion having a second inner periphery configured to slidably engage the second outer periphery of the cylindrical portion of the piston;
• a spring disposed in the annular space between the head portion of the piston and the rear portion of the cap assembly, the spring biasing the head portion of the piston away from the rear portion of the cap assembly;
• and
• a housing coupled to the sound suppressor and removably coupled to the cap assembly, the housing including an internal shoulder configured to abut the head portion of the piston in a nominal position of the booster,
• wherein the piston may be removed from the booster by sliding forward out of the forward portion of the cap assembly with minimal sliding of the first outer periphery of the head portion along the first inner periphery of the cap assembly when the cap assembly is uncoupled from the housing.