Can a shooter easily form 40-72 cases to work in a 1895 405 Winchester?
If so, is the case forming process easy?
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Can a shooter easily form 40-72 cases to work in a 1895 405 Winchester?
If so, is the case forming process easy?
The difference in 40-72 and 405 Winchester is the rim thickness. The 40-72 was the earlier chambering as a black powder round. The 405 appeared in 1904 and was way more powerful and as such, Winchester made the rim thicker on the 405 so it couldn’t be loaded into the 40-72 with catastrophic results…Quote:
Originally Posted by snowwolfe
In my experience 40 72 are incredibly hard to find these days, not that .405 is much easier. I have cases in both calibers from Bertram. rim thickness on the 40 72 measures .058 and .520 across the base of the case head. Rim thickness on the .405 is .071 and .530 across the base of the case head. So, I think you'll have head space issues.
The Handloader's Manual of Cartridge Conversions, Donnelly and Donnelly says that .30-40 brass can be used to create a short case version of the .405. I recently needed to create .35 Winchester cases, which is a slightly shorter and necked down version of the .405 and didn't want to sacrifice many of my limited stock of excellent .405 Hornady brass, not knowing if Hornady is ever going to produce any more. I used both .30-40 and 9.3x74R cases to make useable .35 WCF brass, but there are issues with each.
The .30-40 case conversion was easy. Fireform with cornmeal and trim to a uniform length. However the necks are short, and since the .405 is even longer than the .35 WCF, .405 cases made this way will be even proportionally shorter. .30-40 rims are also a bit thinner, but I experienced no headspace issue. Shorter .405 cases may not be a big problem, since in the .35 Winchester, the short necked cases worked and shot fine. Shorter overall case lengths can be compensated by seating the bullets out a little farther.
The 9.3x74R conversion was trickier, with the biggest problem being that the base diameter forward of the rim needed to be reduced for converted cartridges to chamber. I managed to accomplish this without a lathe with a 3-jaw chuck setup in a drill clamped in a vise and a file. It was slow going, but it worked. There may also be a headspace issue since rims are thinner than a factory .405, even thinner than for the .30-40. While headspace wasn't 100%, there were no major problems with the modest loads tested. Graf's has 9.3x74R Prvi Partisan (PPU) cases in stock.
In the mean time, Quality Cartridge did several .35 WCF runs, and I bought a number of supposedly ready to fire cases from Graf's. The Quality .35 WCF cases demanded case prep before they were suitable to fire. Primer vents needed to be drilled to the right diameter. I broke a decapping pin and had another get stuck before noticing the vents were much too small. Primer pockets also needed to be uniformly reamed and deburred, and all cases needed to be uniformly trimmed to length. After this, the Quality cases worked fine.
If you're lucky, Quality may do another run of .35 WCFs that you can blow out to make slightly short .405s or maybe they will do a run of .405s (.405 Winchester is listed in their catalog). Bertram also lists .405 cases, but Bertram cases are extremely expensive, and I've had issues with spotty quality in .405 Bertram cases (overly thick rims and soft brass that doesn't last).
George Nonte's Cartridge Conversions gives the following instructions on making .405 cases:
Attachment 313933
Thank you Muskeg,
The most informative post on this topic
I sent you a PM. In looking at comparing SAAMI dimensions between 40-72 and .405, they are nearly identical except for very minor differences in rim diameter and rim thickness. The base diameter and length are right what you need. Brass manufacturers all have small +/- tolerances, but you'd be looking at <0.025" in diameter and <0.018" in rim thickness. I got out my micrometer and looked at what the differences actually look like. Almost nothing. In my experience with two M1895s, a Winchester High Wall clone, and a converted P14 chambered or converted to .405 or .35 WCF, that small a difference in rim diameter will not be a problem at all. The extractors can easily accommodate the slightly smaller rim diameter.
The difference in rim thickness is more critical, but that difference is even smaller. I can't say that 40-72 brass won't give you headspace issues, but there is a wide variation already in rim thicknesses between Bertram, Hornady and old Winchester .405 brass, in Quality and Jamison .35 WCFs and in my converted 30-40 and 9.3x74R brass. They all work without major headspace problems in my rifles.
If you need .405 brass to shoot and can't find any anywhere, I think 40-72 brass is a very good option worth taking a chance on. As far as reforming, it may be as easy as full length resizing and trim to 2.58", the same you'd do for new factory .405s anyway. At worst, if primers begin to back out, there are several things you can do. Do nothing and only use light loads, or increase the rim thickness, on the forward side.
George Nonte's "Cartridge Conversions" talks about soldering thin washers made of shim stock to build up rim thickness, but he cautions about the heat required may anneal the case head and ruin it. Nonte's book was written in 1961, before the widespread home use of modern epoxies. I don't see why you couldn't build up a rim by epoxying a (very) thin washer in place. Nonte also says sometimes headspace can be fixed by placing the case over a steel rod clamped in a vise, and then lightly tapping the rim forward around the circumference until headspace is corrected. A third method I've heard is to use a punch at several spots to raise a burr on the forward side to reset the headspace.
Muskeg,
Thanks for the PM and your informative post. I did order 60 of the 40-72 cases. It is worth a try to form them into 405 brass
I have a M95 in .405 and Bertram .405 brass to go with it. I've been looking for a M95 in 40 72 and 38 72 and was figuring to make a few cartridges from my .405 brass. I don't see any problems in doing so. I don't see why 40 72 couldn't be made into .405. I'd try it.
The 40-72 brass arrived. When viewing them side by side with the .405 brass you can see the differences with the rim diameter and thickness. Differences are small. I did manage to score two boxes of Hornady ammo so at least will have 40 pieces of 405 brass for now. My gut tells me the 40-72 brass will work in a pinch after running into the FL resizing die.
It is nice to have options until Hornady makes another run of ammo.
Mine are in the mail. After all the talk about 40-72/.405, I bought the last bag they had.
I've shot the Jamison 40-72s resized and trimmed to length in two .405 WCF rifles, a Miroku Model 1895 and a Winchester Hi-Wall clone. These have only been low pressure loads using a 292 gr plain base boolit over cards and a thin grease wad loaded with 62gr (volume) of Hodgdon Triple 7 (FFg). No problems experienced, 3-4" at 100 without much effort on my part and iron sights, so it could be a lot better with more concentration. About half of the fired primers back out a bit, probably the difference in rim thickness between "real" .405 cases and make-do cases with thinner rims (headspace). Low pressure might also have something to do with it. Again it's not a problem with low pressure loads. In the single shot, I experimented with correcting the headspace by wrapping a thin section of copper wire around the base and that can be made to work, but it's probably best to just use the substitute cases for low pressure loads. I may convert these cases to .35 WCF because after fireforming they should headspace on the shoulder and not just the rim.