GEN 2 Silent Captured Spring (patented) for AR-15-type rifles H2 Buffer Version Includes spacer to allow for installation in both carbine- and rifle-length buffer tubes. Recommended Use: Short-barreled rifles (SBRs) Suppressed weapons Rifles recommended to use an H2 buffer Select-fire rifles Piston-operated rifles Compatibility The JPSCS2-15 will not function with older Primary Weapon Systems (PWS) bolt carriers. The design of the carrier will prevent the rifle from cycling.