I have a modified RPB 37mm flare launcher for sale. The stop screw has been removed, and an extra notch has been added in the lower rail portion in order to more fully extend the launcher to accept longer rounds such as 8"-10" casings. The spring for the latch has been replaced with a weaker one in order to facilitate easier loading/unloading for lefties. One of the screws is stripped for the mounting bracket, all that is required is a new screw. This is for 20" barreled models of the AR15. [s]$165[/s] $150 shipped to your door.