(Disclaimer: I have no connection to Wilson Combat)
This is a Colt 1991A1 .45acp pistol. I replaced the original blue barrel with a stainless steel Wilson Combat barrel because the original owner of the gun never used lube on the barrel's locking lugs (!), and as a result, the locking lugs were worn. Thankfully, the previous owner lubed everything else. This new Wilson barrel is a "drop-in" barrel (well, almost a drop-in), and it is accurate, as you can see. Shown in the photo is an 8-shot group from 21 feet (7 yards), fired one-handed. In fact, with my aging eyes, I'm surprised I can shoot it that well! Anyway, I personally recommend Wilson Combat 1911 drop-in barrels. You may have to do a little hand fitting of the barrel (as I did) but not very much. A few strokes of a stone and presto!, it was in. (The penny on the gun is to cover up the serial number. Sorry for the second photo being fuzzy).