While putzing around the shop I picked up a 6" section cut from a GreenMountain .50 caliber barrel. What could I do with this? Well one thing I could do was to push some balls through it and see how they came out.
First I pushed a .530" Speer ball through to get a good measurement of the bore. It took heavy blows of a rawhide mallet to get that bare ball started but once down 1/2" it pushed very easily on through. I take it this was because pure lead is pretty much non-elastic so once formed to the bore there is very little friction in pushing it on down. I miked the slug at .500" land to land and .520" groove to groove.
Next I tried a .500" cast lead ball in .018" pillow ticking patch lubed with mutton tallow. The combined ball diameter and two thickness of patch totaled .536". Again I could not start the ball with a bare hand but had to resort to the mallet. Once started by mallet I could push it on through with hand pressure on the knob of the ball starter. The .500" ball showed distinct cloth weave pattern corresponding to the lands of the GM barrel.
Last was a .490" Hornady ball with a patch of .026" cotton canvas, mutton tallow lube. Combined total of patch and ball equals .546". This I could start by rapping the starter with the heel of my hand but I probably would not want to do that all day. Once started I could not just push it on through but had to keep striking the starter with my hand to drive it down. The fabric imprint of lands into the ball was not nearly so visible as it had been with the .500" ball, even though the total of patch and ball was .010" greater.
First ball on the left is the .530 bare ball showing bore contact of both lands and grooves. Next, in the center is the .500" ball and .018" patch. Last, on the right, is the .490" ball and .026" patch.
Imprint of the lands on the .490" ball were very light and hard to see, even though the combined ball and patch measured .546". The imprint of lands on the .500" ball was more distinct. Of course the .530" bare ball showed bore contact of both lands and grooves and fins of lead draw out by the lands.
First I pushed a .530" Speer ball through to get a good measurement of the bore. It took heavy blows of a rawhide mallet to get that bare ball started but once down 1/2" it pushed very easily on through. I take it this was because pure lead is pretty much non-elastic so once formed to the bore there is very little friction in pushing it on down. I miked the slug at .500" land to land and .520" groove to groove.
Next I tried a .500" cast lead ball in .018" pillow ticking patch lubed with mutton tallow. The combined ball diameter and two thickness of patch totaled .536". Again I could not start the ball with a bare hand but had to resort to the mallet. Once started by mallet I could push it on through with hand pressure on the knob of the ball starter. The .500" ball showed distinct cloth weave pattern corresponding to the lands of the GM barrel.
Last was a .490" Hornady ball with a patch of .026" cotton canvas, mutton tallow lube. Combined total of patch and ball equals .546". This I could start by rapping the starter with the heel of my hand but I probably would not want to do that all day. Once started I could not just push it on through but had to keep striking the starter with my hand to drive it down. The fabric imprint of lands into the ball was not nearly so visible as it had been with the .500" ball, even though the total of patch and ball was .010" greater.
First ball on the left is the .530 bare ball showing bore contact of both lands and grooves. Next, in the center is the .500" ball and .018" patch. Last, on the right, is the .490" ball and .026" patch.
Imprint of the lands on the .490" ball were very light and hard to see, even though the combined ball and patch measured .546". The imprint of lands on the .500" ball was more distinct. Of course the .530" bare ball showed bore contact of both lands and grooves and fins of lead draw out by the lands.