Recoil booster for firearm sound suppressors

1. 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.

2. The recoil booster of claim 1 , wherein the housing is formed integrally with the sound suppressor.

3. The recoil booster of claim 1 , wherein the piston further comprises a central bore and a plurality of slots at the cylindrical portion, the plurality of slots enabling fluid communication between the central bore and the annular space.

4. The recoil booster of claim 3 , wherein the piston is threadably coupled to the barrel of the firearm, and wherein the each of the plurality of slots is cut at an angle from a radial direction such that pressurized gases flowing through the plurality of slots upon discharge of the firearm apply a force tending to tighten the threaded coupling of the piston and the barrel of the firearm.

5. The recoil booster of claim 1 , wherein the head portion of the piston includes a plurality of spokes defining the first outer periphery.

6. The recoil booster of claim 5 , wherein the internal shoulder of the housing includes a plurality of slots configured to receive the plurality of spokes when the head portion of the piston abuts the internal shoulder.

7. The recoil booster of claim 6 , wherein the housing further includes a first plurality of radial apertures in communication with the plurality of slots.

8. The recoil booster of claim 1 , wherein the housing further includes a forward wall defining the internal shoulder and a generally cylindrical outer housing extending rearward from the forward wall, the outer housing including first external threads configured to couple to the cap assembly adjacent to the rear portion of the cap assembly.

9. The recoil booster of claim 8 , wherein the forward portion of the cap assembly includes an inner housing extending coaxial with the outer housing and from the rear portion of the cap assembly toward the forward wall of the housing, the inner housing and outer housing defining a first annular chamber there between.

10. The recoil booster of claim 9 , wherein the inner housing of the cap assembly includes a plurality of apertures providing fluid communication between the annular space and the first annular chamber.

11. The recoil booster of claim 9 , wherein the outer housing further includes second external threads configured to couple an outer tube of the sound suppressor to the housing, the outer tube of the sound suppressor and the outer housing defining a second annular chamber there between.

12. The recoil booster of claim 11 , wherein the outer housing includes a second plurality of radial apertures between the forward wall and the second external threads, the second plurality of radial apertures providing fluid communication between the first annular chamber and the second annular chamber.

13. The recoil booster of claim 12 , wherein the second plurality of radial apertures further includes a first circular series of large apertures and a second circular series of small apertures rearward of the first circular series of large apertures, the small apertures being smaller in diameter than the large apertures.

14. The recoil booster of claim 11 , wherein the forward wall includes an outer periphery including a plurality of grooves, the grooves in fluid communication with the second annular chamber and an area of the sound suppressor forward of the housing.

15. The recoil booster of claim 9 , wherein the cap assembly further comprises a first cap member defining the inner housing along the forward portion and having external threads along the rear portion, and a second cap member with first internal threads configured to couple to the first external threads of the outer housing and second internal threads configured to couple to the external threads of the first cap member.

16. The recoil booster of claim 15 , wherein the second cap member includes a contoured outer peripheral surface configured to be gripped for rotating the cap assembly with respect to the housing.

17. The recoil booster of claim 15 , wherein the first cap member includes an 0-ring along the second inner periphery configured to seal the internal space from a space external to the booster.