To begin with, you have to get a better measurement of the bore and groove. If your bore and groove are .321 x .323, you only have .001 deep grooves and I don't think any lead bullet will work.

The bore should be ~.315 or smaller.

To know what bullet will work best, we are going to have to have the twist rate. It should be 16 or faster. But, a 16 twist will stabilize either of the Lyman molds you have.

That's still very shallow rifling @ .0015. May I ask how you measured the bore?

As far as a "proven" 2400 load goes, it won't be a "match" quality load as I don't know of anyone that shoots 2400 in matches. I would offer a load of 10-12 gr fixed, to be in the velocity range of match loads.

A well proven match load but, not necessarily a winning load today, would be 14 gr of 4227, half to one gr less fixed.

I might assume that Alliant 2400 is the same burn rate or similar to the old 2400? If so, I've loaded 2400 for decades and have several loads for the .32-40 using both 170 gr. and 185 gr. bullets.
My data came from the old Ideal manuals, and chronograph readings in my Ballard rifles show the data is very close to the manual.

I use 11.0 grs. 2400 with the 185 gr. bullet for 1250 fps. A nice mild load.
I use 12.0 grs. 2400 with the 170 gr. bullet for 1350 fps. The manual shows max load is 14.0 grs. with the 170 gr. bullet at 1600 fps.

You probably need a pin gauge down the barrel to get a decent bore diameter reading. Your slug looks deeper than the rifling depth you suggest.

Do the lands and grooves happen to be odd numbered?

That will play with your measurements.

Frnkeore,
Thanks for this info, I wasn't sure if I could use Lg. Pistol primers or not due to conflicting info on the web.

It's a 6 groove bore but with narrow lands @.040, so a little hard to get an accurate measurement being they're on the shallow side.

Your comments and suggestions are much appreciated.

Mike

From the photo of the bullet I bet you’re measuring at the heel and no way that is correct as one can see the taper of the riflings. Drive the bullet through the barrel and out the muzzle then measure the impression for a more accurate bore number. As for the powder 2400 will shoot somewhat OK but 4227 will beat it any day for match accuracy. Good luck on your endeavors.

Pushing a slug through the entire length of a barrel works, but rarely have I found a bore tighter anyplace else than it is near the muzzle. Long ago I tried this theory out by slugging barrels from the muzzle in about 2", and then the chamber in 2". Then slugged the complete length.
Since most bores tend to have a slight choke near the muzzle during the rifling process I found the tightest measurements at the muzzle. So I no longer slug the whole length, or slug from the chamber. I do a chamber cast to see chamber and a little bore, and then slug into the muzzle a couple inches. This gets me all I need to know about a bore.

marlinguy,
Do you recall the recipe you used in the Gove under lever for the 300yd shots in the Sagebrush  Longshots video ?

Mike

Excellent !!
Did you use any type of filler or wad over the powder and was the 2400 the old hercules or the modern Alliant.
Lastly, was that with pistol or LR primers ?

Thanks,

Thanks marlinguy, once again I appreciate the info.

Mike