Read instructions it is on universal zoom & shoot and I played yesterday online and everything worked fine......A lot of this could be connection based so my advise is to either speed that double shot up or down one depending on your connection speed and try.You made the jump crouch wrong. You made it jump melee.
Change your setting in game to zoom and shoot and try.The gun for me when doing double shot would shoot 6 shots them jump up and shoot 3
Check your ping out to if your latency is high.My connection might not be good enough then
josh try out the TESTER(HALO) rune pack and tell if that is working for you. Button layout is on Universal Zoom & Shoot. The XR on Right Click can go over on your B if you play that way. It will it default press first that is why I made it that way. So it is a BXR or a RCXR.My connection might not be good enough then