Machined 4140 chrome-moly steel barrel extensions help the custom rifle builder ensure a secure barrel fit for best alignment and accuracy. Heat treated for surface hardness to give years of reliable service. Choose from a standard AR-15 rifle extension or an M4 carbine extension with feed ramp cuts. The .002" oversized AR-15 extension provides an extra-tight receiver fit that reduces vibration and improves accuracy, or solves the problem of a slightly loose, out of spec receiver. AR-Style .308 extension fits the DPMS LR-308 and other .308s with the same thread pattern, plus it offers M4-style feed ramp cuts to ensure extra reliability in getting rounds from the magazine to the chamber. All models have pre-drilled locator pin hole; locator pins available separately.
SPECS:
4140 chrome-moly steel, in-the-white. Standard AR-15 - 998" O.D., .750" I.D. No feed ramp cuts. Oversize AR-15 - 1.000" O.D., .750" I.D., with M4-type feed ramp cuts. M4 - 1.000" O.D., .750" I.D., with feed ramp cuts. AR-Style .308 -1.200" O.D., .940" I.D., w/M4-style feed ramps. Fits DPMS LR-308, Remington R-25, and other AR-Style .308 rifles with same receiver thread pattern.
Catalog page 17