Sprue bumps and accuracy.

[wallenba]

Been curious about whether or not there is any evidence, that a sprue bump, significant enough to show through a gas check, has any effect on accuracy. I have a Lee 2 cav rifle mold that, despite my best efforts leaves a good size bump. I've tried 'parking' the flat areas of the sprue plate over them and applying pressure after cutting, but that helps only a little. Might have to try another plate, or just get a new mold. I've been shaving them off with an old wood plane blade. Lots of work time.

[youngda9]

Any bump on a boolit that could offset the center of gravity can only serve to hinder accuracy. Likewise any imperfection to the base of the boolit, especially where it comes into contact with the rifling, can only serve to hinder accuracy. Sprue bumps are generally inconsistent in size/shape and that will affect accuracy.

If you want to know how much you'll have to run the test.

[Wally]

Been curious about whether or not there is any evidence, that a sprue bump, significant enough to show through a gas check, has any effect on accuracy. I have a Lee 2 cav rifle mold that, despite my best efforts leaves a good size bump. I've tried 'parking' the flat areas of the sprue plate over them and applying pressure after cutting, but that helps only a little. Might have to try another plate, or just get a new mold. I've been shaving them off with an old wood plane blade. Lots of work time.

Try to open the sprue plate as quickly as you can...this will eliminate them. On bullets that show them, close and open the sprue plate one more time, before you open the blocks...that will shear the bumps off for you.