BABore
07-27-2005, 10:55 AM
First off let me say that I'm already in-process and have read all the posts and info over on Castpics.
I'm working on a Lyman #457643 mold. My 450 Marlin slugs at 0.4585". Using Either WW's or WW's + 1% tin, the bullets drop at 0.4581". The front scraper band, above the crimp groove is at 0.4595". This mold seems to like 750 degrees plus to get a good base fillout. I'm ladle casting with an RCBS dipper. Both the sprue plate and dipper hole have been opened up a bit based on recommendations from Dan at Mnt. Molds. When everything is at temp she sings. I had some promising groups, then everything went to hell. Quite a bit of leading then I started getting some tumblers. I've been using 2 coats of Alox and the loads are in the 1,100 to 1,400 fps range.
I lapped out the mold once with no real gain. I reread the Castpics post about using the screw to expand the bullet slightly and gave that a try. The bullets now drop with a base of 0.460 avg, middle bands at 0.4582, and scraper band at 0.4595. I cut my lapping bullet off just above the crimp groove.
I did notice that the bullet is slightly out of round. Close to the parting line, but not on it, measures about 0.001" bigger than when I turn it 90 degrees. If I shoot these unsized will that be a problem? Also, since the middle bands are still just a bit small, would you relap just that area?. I'm making up a 0.460, Lee type, sizing die if I get too carried away. Just in case.
I'm working on a Lyman #457643 mold. My 450 Marlin slugs at 0.4585". Using Either WW's or WW's + 1% tin, the bullets drop at 0.4581". The front scraper band, above the crimp groove is at 0.4595". This mold seems to like 750 degrees plus to get a good base fillout. I'm ladle casting with an RCBS dipper. Both the sprue plate and dipper hole have been opened up a bit based on recommendations from Dan at Mnt. Molds. When everything is at temp she sings. I had some promising groups, then everything went to hell. Quite a bit of leading then I started getting some tumblers. I've been using 2 coats of Alox and the loads are in the 1,100 to 1,400 fps range.
I lapped out the mold once with no real gain. I reread the Castpics post about using the screw to expand the bullet slightly and gave that a try. The bullets now drop with a base of 0.460 avg, middle bands at 0.4582, and scraper band at 0.4595. I cut my lapping bullet off just above the crimp groove.
I did notice that the bullet is slightly out of round. Close to the parting line, but not on it, measures about 0.001" bigger than when I turn it 90 degrees. If I shoot these unsized will that be a problem? Also, since the middle bands are still just a bit small, would you relap just that area?. I'm making up a 0.460, Lee type, sizing die if I get too carried away. Just in case.