Smoothbore ball size

[Frog]

I am a new smoothbore shooter and have an original 1842 that has been relined by Hoyt. The bore diameter is .681 by my calipers. I have been trying to shoot a .679 ball which has been a challenge. Some events I only get off 1 round because the balls are too tight.
What I'm trying to get to here is how much undersize should my ball be to be able to load easily and also have good accuracy.
I know of one member on our team who is smoking fast (and accurate) with his '42 and he is using a ball that is .010 smaller than his bore.
I need to buy a mould but want to only buy once cause they ain't cheap!!

Thanks for any guidance.

[MR. GADGET]

Got to be your sprew on the ball.
what you doing to the balls out of the mold?
need to use a ball roller or sprew cutter to make sure that is not the problem.
Also ball mold can be trimmed or decked to cut down on the height of it.

[Carolina Reb]

I'm shooting a Hoyt lined M-1816 that is also 0.681". Measure your balls out of the mold. The Lyman round ball molds aren't always what they claim. (Others may not be either). My 0.678" mold is a lot closer to 0.681" cast in wheel weight. It runs just under 0.680 cast in 50/50 wheel weight/pure. It would probably cast close to nominal size in pure lead.

You can shoot balls at 0.001/0.002" undersize. They are a little slow to ram down as air in the barrel has trouble getting past the ball, but they are accurate. Either cut off the sprew, or be sure it is up when you load. The ball will jam if the sprew turns around against the bore. The popular alox based lubes won't work with balls this tight. You need to use a fairly stiff black powder lube, like bees wax-olive oil or Len's Lube thickened with some bees wax. Dip the entire ball in melted lube. Lots of lube will come off when loading. Don't worry about that. Lube on the ball melts instantly on firing and keeps fouling soft, which is critical. Wrap the lubed ball in wax paper before putting it in the cartridge tube, then throw away the paper when loading. Using this method I've shot entire matches without cleaning and had no loading problems, even got 100% hits occasionally.

[Lou Lou Lou]

For what it is worth I am shooting a .562 Lee ball in my .580 Cadet. Using a set of farrier rasps then twice coated in lens lube , the triple dipped in MCM lube

basically .018 thounsanths undersized

[Rich Foster]

Paul, Your ball size after prepared with light roll of file the max ball size is .675 and min. is .673 if your bore is .681. There should be no sprue on the ball. You will get .001-.002 more on the ball after it is rolled with file. So with that said you need a ball out of the mold about .672-.673. You put anything larger than .676-.677 down the barrel after a few shots it will get tight. If you want some more help pop me a shout at rcfoster90@hotmail.com . Rich Foster, Dismal Swamp Rangers.

[Jim Wimbish, 10395]

Balls shoot just fine at about 12 to 15 thousandths under bore. I shoot a .675 Moose round ball in my .690 H & P. I lightly knurl the balls and dip lightly in my musket lube. They will pretty much just drop down the barrel and shoot every bit as well as a larger ball. I have found no advantage whatsoever to a tighter fitting ball. The larger balls are just slower to load.

[jonk]

I have 3 smoothbores.

One will do just fine with alox. The other two gunk up fast.

If you're going that route, try dipping in melted musket lube, whatever that may be for you. Some say thrice dipped, I never found the need to dip more than once.

By so doing the fouling stays very soft and manageable.

I'm shooting a .678 out of both an 1816 and an 1842. I know both will take a .683 at a snug fit, but neither shoots better with it than the smaller one. So long as you are within 10/1000ths, I think you're fine.

If the sprue turns sideways, that is an issue of course.