At 25 yards with a Colt, I can generally keep all my hits inside a saucer. That said, I am not moving, the target is not moving, and no one is shooting back at me.
I can also do this with most any high quality pistol or revolver in 9MM, .45 ACP, .38 Special, or .357 Magnum. I routinely have other people hand me their pistols and revolvers on the range. After watching me shoot, they think there's something magical about my pistol and want to try it for themselves. Of course there is not, which they quickly learn, it's just consistent practice and an understanding of the fundamentals of marksmanship. I don't have any custom or target pistols so I can't say how good a custom gun would shoot in comparison to my factory Glock or factory Colt pistols and revolvers.
The most accurate .45 pistol I ever had was a H&K P9S that I sold awhile back. That pistol could routinely and easily place all of the rounds in a playing card at 25 yards and had no more recoil than a 9MM.
My most accurate .45 is my 7.5" barrel Single Action Army revolver. At 15 yards, I placed all 5 rounds through the same hole. I thought it was a fluke, but repeated it 9 more times (box of 50 rounds of Remington 255 grain SWC). At 25 yards it will place all the rounds inside a playing card. The trigger is very light, smooth, and consistent. That revolver is, in all probability, more accurate than I am capable of shooting it.
I'm inclined to think that my poor eyesight and my ability to remain still is the limiting factor. Towards the end of my range sessions, my accuracy starts to suffer because my eyes get tired and I can't keep the sights and target in focus.