Ar-15/M16 Adjustable Gas Blocks - Ar Adjustable Gas System, Low Profile .936'''' Bore, Aluminum

Replaces the factory front sight/gas block and allows you to tune the gas system for smoother cycling and operation. Especially critical on match and varmint rifles when shooting both factory and custom-loaded ammunition. Simple setscrew lets you control the gas flow, so you can customize the setting for each load. Hex head setscrews clamp the block securely to the barrel. Installation instructions included.   Low Profile model fits under handguard on .750" barrels. Rugged, all-steel construction resists gas erosion and helps maintain rifle’s weight distribution.  JPGS-5B and JPGS-5S Low-Profile models have a slimmer profile to reduce weight and to fit under a wi Mfg: J P Enterprises SPECS:  Low Profile - Carbon steel, matte black. 17⁄8" long, 1" (2.5cm) wide. .750" I.D.  A2-Style - 416 stainless steel, matte black oxide finish. 17⁄8" long, 7⁄8" (2.2cm) wide, 33⁄8" (8.6cm) high, .750” I.D.