[Nightcrawler]

Could Ruger make a GP100-frame revolver in .45ACP if they wanted to? A six shot one, I mean?

Currently, all six-shot .40-.45 caliber revolvers are on large frames, like Ruger's Redhawk and the N-Frame. (Is the Redhawk larger than the N-Frame or just heavier?)

I was wondering how necessary it is. I mean, cylinder wall width is important if you want a strong gun. I can use my own 25-5 as an example of that. It's a beautiful .45 Colt six gun, with a smooth action and perfect lockup. I can't, however, fire the full-house moderized .45 Colt hunting loads through it because it can't take it. For that reason I'm probably going to buy a .45 Redhawk.

Furthermore, could they make a 6-shot .41 Magnum or 10mm gun on the GP100 frame? Or would the cylinder walls be too thin?

[Sisco]

They probably could but have no plans to do so.
I wrote them a letter asking that question and that was the answer I got back.
Wouldn't mind seeing a GP in 40 or 10mm either.

[Old Fuff]

Nope, Ruger wouldn't even think about doing it. The cylinder was designed for six .357 Magnum rounds. In theory one might be made as a five-shot .41 Magnum or a possibly a six-shot .10mm with full-moon clips. The "big-ten" would work because you don't have to worry about rim clearance between the chambers.

Ruger revolvers are over-engineered to be on the strong side. You won't find them making anything that goes in the other direction.