Can a standard 45ACP barrel be reemed out to a 460 Rowland?
Not advised. Go with the Clark Custom conversion.
The Clark conversion needs the comp on the barrel for the 460 to not destroy itself. I tested one barrel to destruction without the comp, and it does not take long.
With that said, the Wilson factory gun is comp-less, and my guess is that they have accomplished this through VERY precise fitting of the gun.
I would say that unless you have the capability to fit up a gun (espcially the barrel) as well as the Wilson, full house 460's will destroy a 45 acp barrel reamed out.
As noted the specific answer is yes, it's trivial, but DON'T even think about it.
You may be under the impression that the .460 Rowland is an improved cartridge as is common in rifles. That is, in bottleneck rifle cartridges there are improved versions such as the various Ackley Improved or Rocky Gibbs or what have you that increase powder capacity to allow bigger numbers. Folks can debate whether this is an improvement or just a change. Similarly there are long chambered cartridges - Lott - that add combustion chamber length to the .458 Winchester and so it goes. This is not the case with the .45 Auto and .460 Rowland.
The .460 Rowland case is longer than the nominal .900 of the .45 Auto but has no none nada zip extra capacity. The .460 Rowland is loaded to the same OAL as the .45 Auto to fit the same magazines and feed and extract from the same pistols. The brass on the .460 Rowland comes up higher on the bullet - for all I know there may be extra neck tension and so improved performance from maximum loads but at Rowland pressures I expect the powder to burn pretty well anyway.
The only reason I can imagine to ream a standard .45 Auto to .460 Rowland length would be to salvage a carefully and properly fit barrel that has damage in the throat that would be removed in making the change. Given that shooting .460 Rowland ammunition in such a converted barrel pistol would be unwise saving the barrel would be an exercise in futility. Much better to buy a .460 Rowland conversion. Buying the sometimes hard to find and always expensive .460 Rowland brass to load to normal .45 Auto pressures - and so create the possiblity for a confusion caused disaster - would be more trouble than fitting a new barrel in .45 Auto.
The .460 Rowland conversion with its own new barrel and comp is an affordable way to add some excitement to an existing 1911 - but part of the excitement just might be how long is this going to last?
Of course I like the 1911 and I like high performance so my carry gun is a 9x23 and I have a .460 Rowland (from Clark via Brownell's) for the woods (different frames and slides) but I'm very nervous about handloads at those pressures - then again I'm very nervous about factory loads in the .460 Rowland.
One MAY ream a .45ACP to .460 Rowland. But before you do that, buy a box of .45 Super [which chamber in .45ACP], and some stiff recoil springs, ~22#. See if that's to your liking. .460 Rowland is a bit hotter, suggested to be used with a compensator (real) and a 22 or 24# spring. You will want an FLGR to keep the spring from kinking.
It pretty much takes a real MAN to assemble the Clark Rowland.
The extra case length of the Rowland is a safety feature that the Super doesn't have. Capping off a Super round, unexpectedly, with a 14# recoil spring would be an ill surprise.
'course, I shoot all three.