I recently acquired this drilling I Kinda Like Drillings as a replacement for one I lost in a boating accident. It's an 'oldie', having been made in 1898. It's nice that shotgun bores are fairly 'standard', and this one is a common drilling size - 16 bore. However, there's nothing "standard" about how these century-old drillings' rifle barrels were chambered.
As I mentioned in the above thread, the arm was advertised as "10mm". It's not. It's actually 11.2mm (~0.441"). Sorta. Here's a drawing of the profile of the rifling with an attached slug of the muzzle.
A chamber cast (on the right, in the following picture) shows that the chamber length is just a bit longer (~2mm) than a .348 Win case.
Other dimensions of the chamber suggested that .348 cases could be used. Based on the chamber cast, I made a 'prototype' resizing die on my lathe and 'squoze' a .348 case down sufficiently to fit in the chamber. I then swaged a .458" cast bullet down to 0.442", filled the case up to the base of the bullet with black powder, and 'touched one off'.
One of the many 'nice things' about BP cartridges is that you don't have to worry about how much powder to use. With few exceptions, if you know the bullet weight for which the cartridge was designed, you can 'fill 'er up' and have at it safely. While I didn't know what this cartridge was, I had a pretty good idea about what bullet weight was used based on the other 11.2mm cartridges I found that were "almost" this chambering. Anyway, the fired case gave me a good feeling about how well the .348 case was going to work for this firearm.
Using the fired case dimensions,
I ordered a reamer from Welcome To Pacific Tool and Gauge Inc. -- Reamers, Gauges, Bushings, and more. . There was a bit of a SNAFU with the pilot, but that got resolved fairly quickly, and I made a nice full-length resizing die. It takes a bit of 'muscle' to form the body of the cartridge even with the custom-made die. The head of the .348 is about right, but by the time I get finished "squeezing" the body in and down, the head has swollen by about 0.005". The last few millimeters of sizing requires quit a bit of effort. Here's what the finished case looks like between some better-known cartridges. From left-to-right: 45-70 Gov't, .416 x .348 Win (one of my wildcats), the 11.2 case, the .51x.348 Win (AKA .50 Alaskan), and the 'native' .348 Win case.
Next was bullet selection. There aren't any .440-ish jacketed bullets 'out there' available to me. However, having been down this road before, I was not particularly deterred. I would simply swage down bullets of larger diameter, and "swage" up ones of smaller diameter. I ordered four "bullet sizing" dies - two over-the-counter ones from Lee (.455" and .451"), and two custom dies (.442" and .439") from:
501 Lime St
Tunell's dies are outstanding and I can HIGHLY recommend him. The 0.442" die was for cast 'boolits', and .439" for resizing jacketed bullets accounting for about 0.001" of spring-back, yielding a finished diameter of 0.440". When I received these dies, I started "making" bullets.
Here are some images of bullets I started with in the finished 11.2mm diameter:
The left one is cast from the Lee 1R .45 ACP Ball mold and a the right is a "generic" .45 ACP Ball jacketed bullet. Both weigh 230 grains. Finished diameters after swaging: cast = .442", jacketed = .441".
This one is from a Lee custom mold that they had "laying around", nominally 0.446" in diameter. Actual diameter as cast from wheel weights was .448". With gas check it weighs 416 grains. I think it's a bit heavy for my interest, but we'll see how it shoots.
Here is an over-the-counter cast bullet from Oregon Trails. It is a 405-grain bullet in .458". It is the bullet that shoots best from my .45-70 rifles. Finished diameter = 0.442" and finished weight with gas check = 408 grains. Also most likely too heavy for my interest.
This is a bullet cast from Lee's 300 RF-GC mold, nominally .458" in diameter. Finished weight = 303 grains, and finished diameter = 0.442". This is a bullet I am interested in. If it shoots straight, it will be high on the 'short list'.
This is Hornady's .458", 300-grain "LeverLution" bullet. Final diameter, 0.441".
Here are the bunch of them side-by-side:
I have also swaged Hornady's 225-grain .452" LeverLution bullets down to .441", but I don't have pictures of those at the moment.
At this point, it's time for load workup. I've been playing around in QuickLoad, and it's difficult to find a load that is low pressure enough - I want it below 28,000 PSI - and still fills the case at least 75% full. I'm not averse to using BP, but I'd prefer not to for two reasons. First, it's just plain 'messy'. Cleanup - mandatory immediately - is a pain. Second, I seriously doubt I could get any of these bullets to MVs that I would be satisfied with (over 1500 f/s), using BP.
It's been "the Holidays" and very dark here, so there has been no paper-punching. I expect to get out and see how these various bullets 'work' before too long.