The iconic CMMG Mk4LE Upper for .22LR features an accurate, nitride-treated 16.1 4140 chromoly steel barrel with a 1:16 rate of twist in a M4 profile. A2 compensator muzzle reduces muzzle jump, keeping you on target for follow-up shots. F-marked front sight base makes the upper easy to customize. Receiver is a long-lasting forged 7075-T6 aluminum M4 type upper. M4-type two-piece handguards. Type: AR-15 Uppers.