What is the best Diameter bullet to slug the bore of a 40-70 Ballard? I’ve got a rifle soon to be on the way and am looking to get the right size bullets. Any other tips and suggestions are greatly appreciated.

Try egg sinkers - get 'em at Walmart. Nice and soft, and in several sizes.

A .40-70 Ballard bore will usually run around .410"-.411" and I use muzzleloader balls. I have two boxes in .45" and .375" and use the appropriate size to slug bores. 
For bores a bit larger I lay a ball on the flat of my vise and give it a hit with a hammer to squish it. Then measure with my mic to see if it's large enough. Once it expands to cover the size needed I sit it on the muzzle and use a brass hammer to start it, then a brass punch to tap it into the bore. Once it's tapped in below the crown I use a cleaning rod to tap it out and then mic it. Going all the way through is usually a waste of time, as bores generally get larger the closer they are to the chamber. A chamber cast is best forr checking the chamber end bore.

Hopefully you have a source for donor brass like .405 Hornady brass? The only real option is .30-40 Krag and a lot of case stretching after fire forming to get to .40-63/70 Ballard length.

Marlinguy-good info!  I always where people got the balls to check bore/groove.

Thanks Everyone. Val, the owner had 20 RMC brass with the rifle. They should hold me for a bit. Would like to get 20 more. Should be a nice shooter, a #4 perfection. I do try to interest other people closer to my age but it seems to always fall short. My local Gunshop owner however who had never even seen a Ballard in his shop is enamored with them. Every time I show up he says “let me guess another Ballard”

George Babits wrote Today at 10:23am:


George are you saying your Sharps wont accept cases trimmed to the slightly longer .40-70SS? The two cartridges are nearly identical except for the Sharps being slightly longer at 2.5" and the Ballard usually run around 2.4" long.

The 9.3x74R brass is easy to buy, and can work, but has smaller OD rims, so have to be careful chambering or the rim can slip past the extractor on my Ballards. I use the 9.3x74R at full length in my .40-85 Ballard Pacific by just expanding to .410" and fir forming them.

In my Sharps everything is trimmed to 2.5 inches if I remember right.  Yes the 9.3 X 74rims are slightly smaller but no problems with them.  The only brass I trimmed was the Hornady 405, but I had trimmed them when I was using them in a Shiloh 40-70 SS.  What surprised me the most was the groove diameter.  If I remember right, all the books say the Ballard is .403.  Maybe a bore riding paper patch?  When I got the Sharps I figured 40-70 SS was 40-70 SS.  Got a real awakening when I tried to resize the cases in my standard 40-70 SS dies.  The Ballard case is a enough fatter that it wouldn't go in.   Had to have CH4D make me some 40-63 Ballard dies.

George.