CMMG 9mm M4 Upper. Mil-Spec A3 Receiver. 4140 W.A.S.P. Barrel with 1:10 twist.

Note: Ramped 9mm Bolt uses a standard AR-15 or M16 hammer. Do not use with the dedicated 9mm hammer.

Features and Specifications:
Mil-spec certified 4140 chrome-moly vanadium steel barrel
1:10 twist
WASP treated barrel, including The chamber, bore and under the front sight base
"F" marked front sight base.
M4 Single heat shield Handguard
Each barrel is individually magnetic particle tested.