.300 Blackout Rifles, Pistols & Uppers.300 AAC Blackout was designed to cycle reliably from short-barrel AR platforms using pistol-length gas — exactly the configuration Radical Firearms builds our 7.5″, 8.5″, and 10.5″ .300 BLK rifles and pistols around. Supersonic 110-125gr loads for hunting and defense, subsonic 220gr for suppressed shooting, same magazine, same bolt.Why .300 BLKThe round fills a gap 5.56 can’t: short-barrel effectiveness and subsonic precision with a commercially-available can. Our HBAR-profile barrels are chambered specifically for both pressure ranges.Related CategoriesAR-15 PistolsAR-15 Uppers.300 BLK AmmoSuppressorsEvery firearm on this page ships direct from our Stafford, Texas facility to the transferring FFL dealer of your choice. California, New York, New Jersey, and Massachusetts-compliant configurations available on request. NFA items (suppressors, SBRs) require Form 4 processing through your transferring dealer.