I need to get a ball mold made pretty soon. It will be one that is large enough that shrinkage could be a bit of an issue so I figured I better check in here before ordering the wrong one. Barrel measures .998 across the grooves and .985 across the lands. I figure a ball size of about .970 to .975 would be about right. Assuming the ball would shrink by about .5% to .75% as it cools. So if I get a mold that measures .980 it should get me to the correct size. Does this sound about right or am I making a mistake somewhere in here?
Bill, up to the .62's we usually get moulds that are listed as being .005" smaller than the bore side. Oft times, they cast at what the mould says it is, sometimes a bit larger, 7 only the Taner moulds casting smaller than size ordered - ie; due to shrinkage. My .677" (15 bore) mould casts .675", a whole .003" undersize in pure lead and .002" smaller harder (WW) alloy. I can live with that -
I think you are concerned about something that really makes no difference.
.985" bore, between 4 and 5 bore. due to a very tight load as we use in smaller bores, requiring movement of lead and due to the amount of lead that will bear in this size bore, I would order a Tanner mould in .972" or .973". That would allow me to use a very thick patch (.030" or thicker -12 to 14oz denim), which holds enough lubricant to work in this huge bore. A bore that size will be shooting quite heavy loads (in comparison to smaller bores) and thus will require more lube to keep the fouling soft.
What a beast! Wear a PAST shoulder protector. .985" is the size of many of the so-called 4 bores of the day. Yes it is smaller, but that's the way things were. What would "they" call it, a 4 1/2 bore?
The last 4 bore W.W.Greener shot with his recoil measuring machine that went up to 200pounds, broke the machine, with a mere 12 (327.6grs.) dram load, not the 16 (1 oz powder)) dram load considered to be maximum.
detached retinas' are a real problem.