The ramps on the extension are to line up as the cartridge comes off lifter, correct? In other words if I do a single stack something then it gets one ramp? Are there good and bad extensions? Where can you get them and be confident they are good. The barrel extension is what the bolt locks into. Any no no's in that area? Forgive my ignorance of these mighty matters but searching utube can be almost a waste between the vocabulary challenged 900 word base level with the fundamentary words starting with a F ! Yup, I am a old conservative and starting to feel proud of it!!