Adapts Military .250" Uppers Front Hole Diameter To Lowers With 5/16" Front Pivot Pin Hole Diameter.

- COLT Manufactuers Their HBAR Rifles With A 5/16" Front Pivot Pin. Other Makers of AR15 Type Rifles Use The Military Standard .250" Front Pivot Pin.
- Required Part To Attach Non-COLT Uppers To COLT Lower Receivers.