The Original self-regulating piston system is backa |and better than ever! Osprey Defense MSRs feature a newly re-engineered, patent-pending design that makes shooting suppressed and unsuppressed easier-and smoother-than ever before! The new low-profile piston design fits within an ultra slimline handguard, featuring an integrated barrier stop, top side Picatinny rail, and M-LOK compatible slots on all seven sides. The new gas block design incorporates multi-faceted dispersion technology to bleed excessive gas both forward through a gas block vent and evenly around the piston surface. Each Osprey Defense MSR is topped with Franklin Armory's linear-compensating TriumvirA(R) flash suppressor and top-grade furniture options. Best of all, Osprey Defense MSRs are designed to require minimal to no piston system maintenance during a typical barrel lifespan.