REF5 is a 9 position 308 AR compatible receiver extension (RE), it is also compatible with Vltor's splendid A5. REF5 is a collaboration with SOLGW, and is identical to Sons of Liberty Gunworks Loyal 9 A5 RE save for the respective company logo/name engravings. Forward Controls had contributed design input (extra drain holes and softening of sharp corners), there was nothing else we deemed a receiver extension could do better or needed to be improved on, so Loyal 9 / REF5 may look like other REs but with ergonomics and sensible changes, they're made for work, not for show.
REF5 is compatible with 308 ARs and Vltor's A5 system. For AR15/M16 applications, it must use Vltor A5 or A5 compatible buffers, rifle length recoil springs (Vltor's A5 spring or Sprinco's Green spring).
REF5 is made from impact extruded 7075 aluminum with rolled threads. The interior is dry film lubed, the body diameter is milspec (compatible with all milspec carbine stocks), it has extra drain holes to better and more quickly drain water inside the RE.
NOTE: For use on AR15/M16, REF5 requires a Vltor A5 buffer, rifle length / A5 / Sprinco Green recoil spring. REF5 is incompatible with standard TDP spec buffers and carbine buffers.