I have a Springfield 1991A1 frame, I need to know whether it is a .220 or .250. I have used my calipers to measure the grip saftey area and do not come up with either of these numbers.
You shouldn't be getting those exact numbers, IMO. There'll be a bit of a small gap on both sides of the safety with the frame. This will allow easy movement & a allow a bit of dust/dirt reliability.
If you call Brownells, they're usually pretty sharp on what you'll need.
Hope this helps.