Have an old RIA double-stack 1911 that shoots ok in factory config, but the specs seem to be different than Colt specs.
Got a colt 1991A1 slide with a Schuman comp barrel installed from E-bay back when you could get such things there.
When I mate it with the RIA frame, the back of the slide hangs over the frame 1/8" or so, though the barrel seems to be locking up properly.
Don't want to fire it this way though.
That is another issue with these. So many spec issues.