Barrel diameter vs. actual ball size

[Elmer E LaBrash]

I have had muzzle loading rifles in the past, always bullet rifles. My new/old Kentucky rifle has a diameter of.401, 1 twist in about 48" Do I buy a 36 cal. ball and patch to fit? Thanks in advance for any info.
E LaBrash

 

[plmeek]

Assuming your figure of .401 is a good measure of the bore ID, the recommended ball size would be .390" or .395" OD. The ball is usually .005" to .010" smaller than the bore ID. You should try these with patches of varying thickness such as .015" and .020" to see which ball/patch combo gives you the best accuracy.

You can order the balls and patch material from Track of the Wolf, and when you determine which ball works best in your rifle, you can order a mold in that size.

 

[Elmer E LaBrash]

Phil, thanks for the response. The bore dia is correct -- .401 When I lived in MN I was a frequent shopper at the "Track" Great store and the staff is first rate -- waiting for the new catalog. I will shoot the rifle a few times, although it looks like it is in good enough shape to shoot often, but why take the chance of damaging an original. My next (after a list of honey-dos) is build an exact copy of a Pensilvania flint and pistol to match. I am practicing my engraving and scrimshaw -- I,ve got the bug.
It was a good stroke of luck to find this forum.

Regards, E

 

[Zonie]

Your rifle is usually called a .40 caliber. They were very popular for target shooting and as far as I know, they still are.

Track of the Wolf offers a couple of lead roundballs for your rifle. Follow this link and look for the .389 and .395 diameter balls.


https://www.trackofthewolf.com/List/Item.aspx/127/1

The 1:48 twist is just the right value for a .40 caliber round ball shooting rifle.

 

[Billy Boy]

Hi all,
I have a 40 long rifle converted to percussion ( i’m a sport but iv’e got my limits). GM barrel, seems to me the tall lands, deep grooves like a little smaller ball - .390 and a thicker patch than the shallow groove barrels i have which seem to me to do better with a bigger ball and thinner patch.
I haven’t been pestered by the Nobel Committee again this year, you should know....

 

[Griz44Mag]

Deeper rifle, smaller ball, thicker patch.
Works great in my GM 50 cal barrel

 

[hanshi]

I have a double cavity Lyman .40 mold which one of the cavities drops a .400" ball. The other cavity is something less than that. I'm anxious to try the .400" ball in my GM .40 barrel.

 

[Gene L]

Unless you have an even number of lands/grooves, which most don't, you can't get an accurate reading from a caliper. One foot of the caliper will be in a land and another will be in a groove. So go a bit smaller and patch it up.