303 and Cast?

[Larry Gibson]

what alloy are you using

I still have a supply of COWWs so the alloy is COWWs + 2% tin. An alloy of 95/2.5/2.5 will be very close to that. I water quench the bullets out of the mould which gives them BHN of 16 +/-.

[Wilderness]

If you have a rifle with extra large throat, one possibility for bullet fit is to size down 8 mm or .32 bullets. I size .322" down to .312" for .30-30, using Lee .314" then .311" dies. Others size .270 or 7 mm down for oversize 6.5 mms or .321" bullets down to various .303 oversizes. The Lee dies do a remarkably good job on major sizing.

Use the gas check that is correct for the mould. Gas check will dimple (concave) when heavily sized. Lumpy sprues will produce out of round and off centre dimples. Shave bases with a knife to remove sprue lumps and craters lips, but don't try to clean up the pits. This ensures round and centred dimples.

If using this approach, lube before sizing so as not to collapse the lube grooves, and maybe lube again afterwards to ensure the now bare bands are relubed.

Larry Gibson also has posted in the past about sizing next-calibre-up bullets to fit an in-between barrel/throat size.