I posted the following on another forum. I thought I'd post it here too for those of you that don't venture beyond this forum.
Okay cap-n-ballers….don’t hate me. I decided that I wanted the option of shooting cartridges in my Walker in addition to shooting cap-n-ball style. I purchased a Kirst Konverter and had a channel cut in the recoil shield to allow for breech loading of cartridges. There are a couple of things about converting a Walker to shoot .45 Colt that always bothered me. (1) The .45 Colt cartridge only allows for a maximum of 40 grains of BP whereas the Walker in cap-n-ball style can hold up to 60 grains. (2) The relatively short length of the .45 Colt cartridge means there is quite a bit of bullet jump before the projectile gets to the forcing cone. Seems that with the convenience of a cartridge conversion you can’t have your cake and eat it too. I thought I’d do something about it (because I like cake) to get a little bit more flexibility when it comes to cartridge shooting. Sheesh, do I have too much time on my hands or what? FWIW, you non-engineers should know that most of us engineers spend way to much time thinking about solving problems even if they don’t really exist and we have to create a theoretical problem out of thin air.
Enter the .45 BPM. This cartridge addresses the two issues I mentioned above. (1) The .45 BPM can hold 60 grains of BP. (2) The cartridge is longer and therefore the projectile can sit much closer to the forcing cone. There was a little work that had to be performed on the Kirst Konverter. The rim recess diameters had to be increased slightly and each chamber had to have the rebate depth increased. It will still hold .45 Colt cartridges.
This is not an idiot proof solution. Any self proclaimed idiot or bed wetting tree hugger may want to stop reading here. Cartridge reloading, in general, isn’t idiot proof. Attempting something foolish with any cartridge reload could lead to disastrous results. I say this because I don’t need to read someone post “What’s going to happen if someone accidentally loads the cartridge full of Bullseye and tries to shoot it out of a Walker?” Well, what do you think is going to happen? Probably a junior version of if someone loads up a .45 Colt cartridge with Red Dot and tries that in a Walker. Right?...just a smaller mushroom cloud.
Note that no where in this thread will you see me advocate loading up a .45 BPM cartridge with 60 grains of BP and firing it from a Walker. I only mention the maximum capacity because I know someone will ask. It is possible it could make for a fun little carbine rifle cartridge. Without thorough testing and analysis I have no idea what kind of pressure may be generated. It depends on the firearm, the amount of BP used, and the weight of the projectile to mention a few important factors. I am confident, however, that there is room for shooting more than the 40 grain limit of a .45 Colt in the .45 BPM. There are a few BP bullets that may be of interest to try out with more than 40 grains of BP. Specifically, one example is a 150 grain BigLube .45 caliber bullet that may be a good substitution for a round ball. Speaking of round balls, there isn’t any reason you couldn’t load up some “gallery loads” using your typical soft lead round ball. When I say “gallery load” I’m really not talking about in the traditional sense. Rather I mean it as a cartridge loaded with a round ball. A round ball with 50 grains of BP just may be a decent substitute for shooting a Walker cap-n-ball style with a similar load of BP.
I still plan on shooting this Walker cap-n-ball style. I just thought I’d mix it up a bit by having the option to shoot the .45 BPM cartridge in it too. I haven’t shot the Walker yet with a .45 BPM cartridge. I’m still waiting for the weather to cool down a bit more. ClemBert’s shooting range looks like a hayfield right now. The last hay cutting for the season should be soon then I’ll be good to go. The first loads will most likely be 40 grains of FFFg, grits for filler, and a 250 grain BigLube bullet. Without further adieu, here are a few pics for your viewing pleasure.
.45 BPM (left) .45 Colt (right)