The Grey Birch Solutions LDR Fusion Barreled Receiver System has the same footprint as the legendary 10/22(TM), but that is where the similarities end. The Fusion Receiver System (FRS) is a 10/22A(R) compatible threaded barrel system that offers increased stability for consistent and accurate shooting. Threading the barrel and receiver into a single unit overcomes a significant flaw found in most semi auto rimfire rifles. The barrel is typically levered in place with either a v-block or grub screw. The disadvantage of using a v-block to attach the barrel to the receiver is a loss of elevation or windage due to tolerance differences between the barrel and receiver, allowing the bar Mfg: Grey Birch Solutions