Actually, shooting a 1911 at 100 yards is a lot of fun. Just this past Saturday we were shooting pistols and rifles (pistols at 2 to 25 yards and rifles at 100) and at the end of the shoot I unloaded a clip of .45 at 100 yards with decent results. Holding towards the top of a 16" centerfire target I was hitting within 6" of bullseye. Like Don has found, the front post of a handgun is simply too wide for very fine accuracy past 25-30 yards...even with my Kimber Target II.
If you really want to have fun, put a 2 liter coke bottle full of water at 125 yards and see who can hit it with a pistol.
"Shoot low boys...they're riding shetland ponies in search of true grit" Lewis Grizzard