While you are on the site, in your browser find and click "Add to Home Screen" A CGN beaver app icon will then be created to your phone that is directly link to the site.
Note: This feature may not be available in some browsers.
the base diameter of the shell is .406 and the bullet is healed to .386 which is the inside diameter of the shell. The outside of the bullet would be sized to your particular bore diameter. Chamber length varies depending on the model of gun. The chamber of a SAA is about .2" longer than for a Thunderer which means that you can use longer shells in the SAA for the same amount of exposed lead.
The most extreme deviation that I have had was a 38-40 rifle with the original barrel and a measured bore of .410 for bullet with a published diameter of .401. I modified the chamber to accept larger bullets and it shot very well with 41 mag pistol slugs.
Bottom line is to slug the bore of any older rifle and determine what the real measurements are for that particular gun.
I had a thunderer made in 1878 that mic'd at .410 straight through the chambers. An 1889 I had mic'd at .405-.407 straight through the chambers. Ive heard of some of the later models having a slight taper in the chamber (due to the change to the hollow based slugs)
Given that the case dia is supposed to be .405/.406 and my original heeled mold casts at .404...a chamber dia of .405 would be really tight!
...interesting enough, the bore on this thing slugs at .380