No, it will not fit a bull barrel 1911 of any length. This type of comp is called a barrel bushing compensator. The idea is it replaces the 1911's barrel bushing. In essence, it's a barrel bushing that protrudes a long ways after the end of the slide; this protrusion then has slots or holes drilled into the top of it -- making it a compensator. As I'm sure you're beginning to see, it's incompatible with bull barrels because they don't use barrel bushings. They just thicken the end of the barrel so it becomes its own bushing. But since there isn't a barrel bushing, a bushing comp like this one can't replace it. It's designed to fit on the outside of a regular barrel, in between the barrel and slide. I don't know of any type of compensator that will work with a bull barrel, as to my knowledge there is no such thing as a threaded bull barrel. Your only option would be to talk to a first rate gun machinist, and see if they could drill slots through both the slide and barrel. Never heard of it being done, but I suppose in theory it could be. Would be costly and risky, but can't hurt to ask.