I've got some questions concerning my new M25 Mountain Gun.

I'm planning on reloading for it. What are the chamber dimensions, throat dimensions, and barrel dimensions for these guns? I've read a ton about the Ruger Blackhawks being actually too large, even though they're within the industry allowable tollarances. I've also read that barrel dimensions run from the .454 of the true 45 Colt, to .452 of the 45 ACP. I think all of these dimensions would probably come into play when buying components and the actual reloading of the cartridges.

So, what is the skinny here and what should I look out for? I'm only planning on loading the plinking, target type loads.

Thanks.

SgtSam

Actually, the Ruger Vaquero and Blackhawk in 45colt frequently had undersized chamber throats, with each of the six throats often varying in size as well as being to small in diameter. I just reamed out my Ruger Vaquero. It's throats varied in diam., with the average being around .4504. The standard reamer from Brownell's is designed to ream the throats to .4525. I reamed both my 45colt and 45acp cylinders for the Vaquero, since I shoot the same .452 lead bullets thru both. The goal is to have the bullet you will be shooting pass completely thru the cylinder throat with mild finger pressure. Formerly I could not force the .452 lead bullets, (or .451 diam. 45acp bullets) thru any of the throats. Now they pass thru with mild pressure. The Vaquero not shoots much tighter groups, but seems to prefer the 45acp cylinder for some reason.

By the way, I also have a 45colt 25-13 Mountain Gun, and all of the cylinders on it pass the lead bullet with mild pressure test, measuring between .4522 and .4525. I load .452 RNFP 255 gr bullets to 900fps in the MG, and they are quite accurate. My 22-4 45acp revolver shoots the same bullet at 950fps, with 2gr. less powder, and is equally as accurate. It's throats are slightly tighter than the MG's, but it's designed for 45acp with .451 bullets so I didn't bother to ream it. Didn't need to with the accuracy level it provides even with the .452 bullets. I carry the 45acp more than the 45colt, now, since it matches the 45colt performance and has fixed sights, which I prefer.

I'd suggest you get some .452 lead bullets, and try pushing a few thru each chamber throat. If you can push them thru with thumb pressure so they drop out the charge end, you don't have a throat problem. To the best of my limited knowledge, S&W resolved the throat diameter issues halfway thru the 25-5 version, with the 25-5 models with pinned barrels being the ones that still had tight throats. I believe all 45colt MG's are fine, but I could be wrong. More knowledgeable forum members should be able to let give more precise, and accurate info.

Good luck and happy reloading.
Hastings

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Hastings

I have two .45 Colts (two Ruger single actions) and two S&W Model 625's (a 5" 625-6 Model of 1989 and a 4" 625-8 Jerry Miculek Special) both chambered in .45 ACP.

The Rugers had undersize cylinders that I reamed to .4525" - they now are accurate and exhibit NO leading.

The Smiths came with proper dimensions and shoot extremely well, also.

I shot my own cast bullets sized to .452" in all of them with excellent results.

Dale53

While cylinder throat dimensions are obviously very important, let's not forget the rest of the chamber. Practically all .45 Colt chambers tend to be very sloppy in the case head area. This causes the brass to be worked excessively, even with moderate and completely safe loads. The end result is crooked case mouths that can not be crimped evenly. This is the reason I traded away my 25-7. My Bowen Redhawk chambers had been cut with a small body reamer and they do not have this problem. As a result, resized brass that had been fired in the 25 would not fit into the Redhawk. A Blackhawk I briefly owned also had this problem, though not as bad. The manufacturers seem to be unwilling to give us properly cut .45 Colt chambers, possibly out of fear that their customers will use heavier and heavier loads. This is too bad, because the .45 Colt is a great cartridge even when not hot rodded.

Dave Sinko

I have one of the early Blackhawks. I got it in '74 or '75. It had a counterbored cylinder that had .457" dia. throats with a .452" dia. barrel. It shot poorly, to say the least.

I sent it back to the factory and now it has .452" throats but I lost the counterbored cylinder in the process. It shoots better. Not great, but better.