I've got a 25-5. It'll take some over-pressure loads. There is currently no recognized standard by SAAMI for over-pressure loads in the .45 Colt, so make sure that the next guy's "+P" is your "+P".
I'd say the 25-5 is between standard and T/C/Ruger levels. I have a Blackhawk as well as the Smith, and there isn't a big difference in cylinder wall thickness, however, Ruger decided to place the cylinder stop notches in a better location.
John Linebaugh figures the 25-5 is good for an absolute maximum of 32,000 psi, since the walls are 80% the thickness of the Model 29. I feel no need to go anywhere near that. There is much that I can do and still keep it at 20Kpsi and under.
If you're getting an older S&W 45 wheelgun, as opposed to a Mountain Gun, check those chamber throats. My gun has generous throats, so it tends to do better with bullets sized .454-.455".
Of course: The SAAMI maximum average for the .45 Colt is 14,000 psi. You go above the SAAMI maximum average pressure at your own risk!