I’ve done a good bit of loading for various .40 caliber rifles I’ve owned. These include .38-40, .401 S:, .40-60 (Colt pump and Marlin M1881), .40-65 (Winchester ’86 and Marlin 1895), .40-72, .40-75 Bullard, .40-82 and others. Other than the .38-40 and the Bullard, I thought all used .406 bullets. I see Cartridges of the World lists the .401, .40-72, .40-65, .40-82 as .406 diameter. The .40-60 Marlin is listed at .403 and the .40-75 Bullard is listed at .413 (I use .406 bullets and they shoot well).
I ran in to this Ideal reference:
http://gluedideas.com/content-collection/american-small-arms/The-Ideal-System-of_P7.html
406150. This is the regular factory bullet for the .40-72-330 Winchester. The diameter is .003 larger than all other .40 caliber Winchesters. It is the only .40 caliber bullet having a round point, which is preferred by many. The other .,,,o caliber bullets that are large to be sized will fit nicely.
I had no idea that the .40-72 took a different bullet diameter than the .40-65, .40-70 and .40-82.
What experience have other’s had? Any experiencing slugging the bores of .40 caliber Winchesters?
Thanks
Steve, The most experience slugging bores was for the 1895 book. In it, with dimensions added from a number of other folks, the groove diameter for the .40-72 was from .406 to .407. I believe this comports well with old documentation as well. I have little data on the other 40 calibers (excepting the .405 which I have a LOT of experience with) to give you an answer there. If you wish to include the .405 Win, its “bore” was .405 but the GROOVE diameter, which is the critical measurement, is usually in the .413 to .415 range. I would feel lucky to have a tight groove diameter in that caliber! Tim
For those interested, here’s another good vintage Ideal reference:
https://castbulletassoc.org/download/Ideal%20moulds%20-%201929.pdf
tim tomlinson said
Steve, The most experience slugging bores was for the 1895 book. In it, with dimensions added from a number of other folks, the groove diameter for the .40-72 was from .406 to .407. I believe this comports well with old documentation as well. I have little data on the other 40 calibers (excepting the .405 which I have a LOT of experience with) to give you an answer there. If you wish to include the .405 Win, its “bore” was .405 but the GROOVE diameter, which is the critical measurement, is usually in the .413 to .415 range. I would feel lucky to have a tight groove diameter in that caliber! Tim
Tim – thanks for the response. I am intrigued by the .405 in relation to my .40-75 Bullard. As I stated at the beginning, the listed groove diameter for the Bullard is .413. I would think .405 bullets in the .413 to .415 range would be a choice to consider. Of course, the .405 bullet was typically longer and not designed for use in tubular magazines. On the other hand, it’s not like all that case capacity is needed when using smokeless powder in these old black powder cartridges – hence the bullet could perhaps be seated deep enough to cycle through the action.
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