psa jakl 300 blackout uppers are now available! This upper utilizes a long. This platform is built around a 6105. mar 2, 2024 · one of the standout features of this firearm is its buffer system, which is fully captured in the upper receiver. This design choice shortens the overall length of the. psa jakl 8. 5 300 blackout 1/8 nitride complete upper with bcg, bolt catch & roll pin
