As RC has noted, custom rugers are VERY strong, and it's primarily the cylinder being put in, usually a 5 shot, that is designed to take those kinds of loads.
Linebaugh used 17-4 stainless for the cylinder on my Seville, as does FA for it's guns.
Proof is about 90 PSI before they blow.
Seyfried just kept putting H110 into a colt cylinder, in a six shot, like my old gun, until he got the velocity he wanted, or maxed at.
Back then used to load a full case of H110 under a 230 grain super hard cast bullet for plinking. 33 grains or so?
IIRC, and this is strictly a limited use at your own risk load, over 24 grains of H110, WAY over 24 grains.
Rugers are so strong it takes prolonged use of extra heavy loads to really stretch the frames. A custom can take .454 level loads, and, since the cylinder is longer, the OAL is longer, so you can use heavier bullets, with more velocity then the .454.
I could be wrong on that. It might have been in the day that the longer heavier bullets were designed for the .45 Colt, and finding a .454 bullet
that heavy was the problem. Not sure on that.
I do remember both Linebaugh and Seyfried saying they liked the .45 Colt
because it did better with heavier bullets.
Keep in mind Linebaugh lived in the sticks, and used a 25-5, IIRC, for about 100% of his food hunting. Around 250 grain bullets, cast, at 1200 fps, IIRC. As others have said: dead deers.