Mountain Gun
This is an interesting tidbit that I read from the February issue of Handloader concerning the Mountain Gun:
Manufacturers are extremely careful as to load recommendations and pressure levels used in their guns and understandably so. Nonetheless, your Smith & Wesson Model 25-13 will safely digest loads of greater pressure than the traditional .45 Colt factory load (which is well below SAAMI suggested limits of 14,000 psi). The Model 25 (and 625) N-frame is identical to the Model 29/629 .44 Magnum and is clearly strong enough to handle greater pressures and horsepower than factory .45 Colt ammunition. On the other hand, the chambers are not as thick in the web or outside wall dimensions and cannot handle as much pressure as the .44 Magnum. For a couple of reasons, at this moment I am not willing to suggest “maximum” loads for your Model 25-13 .45 Colt; however, in studying the various Model 1917s, 25s and 625s that are chambered in .45 ACP, these guns have the same basic outside cylinder and outer chamber dimensions and are occasionally slightly thinner. The difference is that the .45 ACP is operating with a SAAMI maximum average pressure of 21,000 psi and 23,000 psi in +P persuasion. The point being that your Model 25-13 .45 Colt is safe with loads that generate 23,000 psi, while retaining the necessary 100 percent margin of safety.
With all that said, the .45 Colt handload containing the 280-grain cast bullet from RCBS
mould 45-270-SAA driven with 7.5 grains of Hodgdon Titegroup and ignited with a CCI 300
primer is generating around 14,000 psi and is absolutely safe in your Smith & Wesson. This
load should produce near 950 fps from your revolver with a 4-inch barrel (depending on bullet alloy and lube) and should be suitable for hunting any game in your region.
I almost bought a Mountain Gun and didn't because I always heard that they aren't strong guns. After reading this I wish I would have bought it.
