For your AR15, M16, M4. A5 receiver extension (buffer tube) machined from 7075T6 and manufactured to Mil-Spec dimensions and specifications. Mil-Spec receiver extensions have a slightly smaller dimension where the stock slides on.
These tubes should be used with stocks such as USGI, BCMGUNFIGHTER™, Colt, LMT, SOPMOD, VLTOR, Stag Arms, and others that a made to the Mil-Spec size.
*NOTE* These buffer tubes require a rifle action spring and specific A5 buffer, carbine and rifle buffers will
NOT work.
If you require a complete A5 kit, please click
here
well made alternate for A5 use 
