Variable Mass Piston, Metal Base SP-MK14-13-BK to prevent the inner barrel

to prevent the inner barrel from protruding beyond the outer barrel

*Please note

The new version of the flute-type NPAS valve is now adopted in

and consistent performance

Outer barrel for the AR15 / M4 AEG series

Variable Mass Piston, Metal Base SP-MK14-13-BK to prevent the inner barrelCNC steel version of the variable mass piston body, for extreme mass configuration (55. 1 grams instead of 19. 0 grams for the aluminum version). Compatible with: original SRS piston (SBA BPS 13) original TAC 41 piston (SBA BPS 30) variable mass piston for SRS (SBA BPS 18) variable mass piston for TAC 41 (SBA BPS 31) original SRS piston end (SBA BPE 01) original TAC 41 piston end (SBA BPE 03)