Replace the stock plastic barrel retaining nut and clamp with our sturdy aluminum barrel retaining nut and aluminum clamp. Fits 1301 and A300 Models with a factory 7 round magazine tube. Clamp features M-LOK accessory slots on each side. This allows versatility for a wide range of accessories over the stock QD swivel, including rails and lights. Must use M-Lok accessories, the Nordic Components QDA-BCL-ASM and TRL-BCT-150K will not fit this product.