There are too many variables to make such a sweeping statement. A custom 1911 race gun is certainly up there. But some of the most accurate combat based designs would have to include the Sig P210 and HK P9S Sport. Don't discount the Desert Eagle in .44 Mag, either. I've read a test where 5 different types of off shelf ammo in an off the shelf DE ranged from 0.99 to 1.5 inches at 25 yds, with most being 1.3 inches or better. And I have no doubt that gun would do very nicely at 50 yds. The M1 Carbine like short stroke piston in the gas system used by the DE does a nice job of minimizing recoil, and weighing 4.5 lbs doesn't hurt, either.
But again, we're getting into variables.
Mauser Werke, Schmidt-Rubin, Colt, Walther, HK, Weatherby, Browning, Ruger, Savage, Bushmaster, Marlin, Mossberg, Saiga, S&W, Sig Sauer....a few friends of mine