Well made & compact - Maxim Defense Industries AR15 Ultimate CQB Pistol Bundle - PDW Brace, CQB Buffer and Spring

The Maxim CQB brace bundle is everything one would expect-quality, great fit/finish/function-BUT, if you are building a 300 blackout pistol with a carbine length gas system, the recoil spring is too strong, and your gun will not cycle. An inquiry to Maxim revealed that they do not have a alternative (softer) spring available, unless you go with the silent capture system. Most web discussions about gas systems encourage a pistol length system for proper functioning...they are correct.