Using the method from the 7.62X54r link, the sinker became very tight after approximately 3" in from the muzzle. There may not have been enough grease after the sinker entered the muzzle ... a lot came off upon entry. Being the first time I slugged a barrel, I didn't want to force the issue, so I tapped it back out. I measured as instructed in the link and came up with .430.