Here's what happens. If you remove the slide lock and install the slide up to the point where it gets stuck, you will have just run over the top of the locking cam. That cam fits up against a ramp on the inside of the slide plate. With that in place you can pull the trigger all the way, but the cam will not move downward to free the slide. If you move the slide back a bit it will. But I don't think you can move it back far enough to clear the cam if the lock is already butting up against the rear of the barrel lug.
This means the only way to remove it is the way you did it Higgy. Not desirable, but I believe it would be the only way. Pushing the slide against a workbench as I suggested earlier would not move it back enough to clear the cam and allow it to descend, because the barrel lug is already tight against the slide stop.
This means the only way to remove it is the way you did it Higgy. Not desirable, but I believe it would be the only way. Pushing the slide against a workbench as I suggested earlier would not move it back enough to clear the cam and allow it to descend, because the barrel lug is already tight against the slide stop.