I originally planned to use .445 Powermag as the donor cartridge, but the brass is very expensive and must be special-ordered online. I also considered .444 Marlin, but not only was that not much better then the .445 in terms of availability, but the case flairs slightly towards the base and might necessitate special reaming, which would make shooting .44 Colt problematic.Â I finally bought some .303 British ammunition, which fits well at the base and has a rim. It also wasn’t absurdly expensive.
First things first I used the bullet-puller. The 180gr bullets were set aside and the powder discarded. Then I cut the brass at the edge of the shoulder, giving an overall length of 1-11/16″- right in the middle of the estimated range needed. I then tried to fire-form the brass, erring on the side of caution by using a thick wax plug over a substantial powder charge. No joy. Rather than fussing with that further I set to work on 1/2″ brass rod in the lathe. I produced two tools of increasing size, and a steel block bored and reamed to .454″
Insert the de-primed brass in the block, hammer in the smaller expansion rod, remove and hammer in the larger. I refined the shape as I went and was very quickly producing credibly straight-walled brass. OK so far.
Next I measure how deep the heel-base bullet went in the case and found that approximately 14 grains of Trail Boss would fit without compression. Backing off to approximately 70% of that load gave 10.0 grains- according to Hodgdon’s data this should be the recommended starting load for my cartridge.
Using my home-made swage I made the 200gr. heel-base bullets to be a tight fit in the cartridge- so tight that once seated with a soft mallet they could not be removed without using pliers. I experimented with my collet-crimp die and the results were not entirely satisfactory, so I tried a ‘chemical crimp.’Â Basically I glued the bullet in with blue Loc-Tite. This works quite well actually, and in the limited testing I have done the bullets do not ‘walk out’ under recoil. I’m satisfied with this arrangement, but it feels like cheating so I am going to continue to experiment with the crimping die.
So how is it to shoot? Recoil isn’t bad at all; I imagine the gun’s 3-1/2lb. weight helps with that. Muzzle blast is loud but muzzle-flash is less apparent than I expected. I do not yet have a chronograph so I have to guess at the velocity.Â The math I have done seems to indicate a muzzle velocity of around 1100 fps., and the rounds sound supersonic to my ear.Â If this is accurate the gun is producing 537ft/lbs of energy at the muzzle. They hit pretty hard too- in my one penetration test the round penetrated 4″ of seasoned Beech wood before exiting the side and burying itself in the backstop. I’m pretty happy with that. I’ll develop some loads with heavier bullets after time and repeated firing have ‘proved’ this load.
The two questions that come to mind regarding this project. The first, which has often been asked, is, ‘You’re using the original Italian cylinder? Are you nuts?’ Yes, I am using the original Italian cylinder. I may very well be nuts- but not for that reason. As near as I and other more experienced folks can tell these cylinders are the equivalent of 1018 steel. The tensile strength of this material is well known, and the math says the cylinder will hold up to these loads just fine. In fact it suggests that a full 14gr. load would be fine, but I’m not going there. Yes, this is just a guess, but it’s a good guess backed by math and practical considerations. The practical consideration is that this cylinder is designed to withstand the maximum charge that will fit in it’s original form- 65gr. of black powder behind a 173gr. ball. The available information suggests that my load generates significantly less stress than that load in terms of both pressure-curve and recoil; black powder is pretty violent stuff.Â Suffice it to say that yes, I guessed it would be OK- but it was a very well-informed guess.
The second question is ‘Why?’Â That’s harder to answer. This gun does nothing that modern firearms won’t do better. The only answers I have to this are, ‘Because it’s cool,’ and ‘because it was fun to do.’Â It’s cool because I did it myself, and no one else has done exactly this conversion before. Yes, others have done big-cartridge conversions of Walker reproductions before- notably Gary Lee Barnes’s .45-60-225 ‘Brimstone’ conversions. But mine is the first using a heel-base bullet and uses a proprietary case of my own devising.
Here’s the idea- if someone in the 19th Century wanted a high-powered cartridge revolver- maybe as a sort of revolver ‘Howdah Pistol,’ they could have done exactly this conversion, and it would work exactly as it does today. The goal here was never to improve the state of the art; it was to make something fun and historically plausible. It does succeed in that- this gun is significantly more powerful than a period .45 Colt. In fact it is more powerful than any revolver cartridge of the period, excepting 11.3x36mmR used in the Gasser and Montenegrin revolvers in Europe.
But mostly this, like many of my other projects, is about finding, pushing and ultimately expanding the limits of what I can do- and creating something unique and, for lack of a better word, cool. Mission accomplished.Â Now I need to make a holster for this beast… and come up with a name for it.
Michael Tinker Pearce, 13 Feb. 2018
Tinker, I think you just created the 1875 equivalent of the S&W .460 “Bear Emengency gun”… way too cool! Thanks for this great blog!
Brad Bradsher, member THR 1860 and Walker club
My pleasure- and thanks for the kind words!