Determining ball size?

[Jim Curlee]

I'm getting a new rifle.
It has an H&H barrel, with round bottom rifling.
The guy that made the rifle, said that H&H called it a 58.
The builder told me he had to use a 560 ball, to be able to shoot the gun.
My question is;
What is the best way to determine the ball size to be used?
If it involves measuring the bore, do you measure to the bottom of the rifling, or just the lands.
Jim

[Frizzen]

Measure land to land and use a ball .005 under and .017 thick blue & white stripe pillow ticking
ought to work real fine.

[The other DWS]

Land to land gives bore diameter.  The ball should be just little less that than.  Bottom of groove between lands to bottom of the groove on the other side is groove diameter.  Subtract bore diameter form groove diameter divide by two and you get the rifling height.  

The operational theory is that the patch should fill the space between the ball and the bottom of the groove with enough compressed padding to provide a gas seal, clamp the ball tightly with out distorting it and grip the rifling enough to provide the gyroscopic spin to the ball that makes a rifle accurate.

Many rifles are nominally a given calibre, .45 .50 .54 .58 in some cases its the bore diameter in others the groove and in some not quite either. (f.i. many 58s take a 577 bullet or ball)   The only way is to know for sure it to take careful measurements.  A slightly undersized ball can be made to work well with the proper patch thickness.  An oversize one will require undue force loading and reloading and the ball can be distorted damaging the accuracy potential of the shot.

There are lots of little details with their own little devils.  patch material, lube on the patch, bore condition etc etc need to be worked out for each rifle.  The way the muzzle is crowned can make a big difference in how well the rifle can be loaded with the properly thick patch material.

But the key to getting started is to know exactly what your bore and groove diameters are.  They can be measured pretty easily with a good vernier caliper if your bore has an even number of lands and grooves.  If they are odd numbered there is a way----but I don't know what it is.     Good luck

[Jim Curlee]

Thanks guy's.
Thats exactly what I needed to know.
Jim

[Daryl]

Be aware, Jim - that the barrel might be undersized, or normal wherein the person needing the small ball might like to push it into the bore with his thumb and the little ball is needed for that method of loading.

There could be different reasons, is what I'm saying. The 'guys' have the measuring perfectly.

Lyman shows a good 'test' for ball patch fit in their old book.

[robert]

I use the biggist ball that will freely fall in the barrel and adjust the patch size after that. About .018 should do it. A larger ball seals better than a thick patch!