I used to think "full size" was a classic 5" 1911 and anything shorter was "compact" or "sub compact" but these days I see a lot of LEO trade ins come in at 4.25" for the main issue guns and shorter for the backup guns. You can clearly tell if they show up in pairs like that. Traditionally LEO guns were full size since concealment was not really a major concern. Is 4.25" now considered full size?