These O-rings will replace any worn, deformed or lost rings from any JP Silent Captured Spring or Variable Mass Operating System (VMOS™) bolt carrier. Replacement of O-rings should take place when you start to see fraying or cracking of the rings. This will happen sooner in the case of 9mm carbines, around 5000 rounds.
These O-rings will replace any worn, deformed or lost rings from any JP Silent Captured Spring or Variable Mass Operating System (VMOS™) bolt carrier. Replacement of O-rings should take place when you start to see fraying or cracking of the rings. This will happen sooner in the case of 9mm carbines, around 5000 rounds.