Sizing lead bullets

[PWC]

First off, I don't cast, but I find the process interesting.

When sizing lead, does it shave off the parting line or squeeze it back onto the bullet? Swagging (means squeeze not cut) down a bullet from "oversize", I assume, keeps the same weight, but lengthens the bullet a couple thousandths, which I don't believe is enough to affect ptessure...except in the smallest cases like .25 or .380 and some powders. Does it?

 

[Walkalong]

It squeezes the whole bullet down in diameter, no shaving. The length of sized vs unsized is so minimal I can't see it being an issue.

 

[JimKirk]

You would have to measure with a micrometer to measure the difference...

Unless your bullets are really huge to start with ....and you will know it when you pull the handle down ...

 

[NuJudge]

Very old sizing dies apparently did scrape off some Lead. I can remember warnings from old publications on setting up Lubricator sizers, when my father first started casting bullets in the 1960s. More modern sizing dies have tapered throats, and will squish diameter smaller. This may do several things, in extreme cases wiping out your lube grooves. There might be some lengthening effect. There is one guarantee, however, and that is sizing a bullet down in diameter has a negative effect on accuracy.

 

[PWC]

Thanks

 

[mdi]

Sizing bullets with sizing dies and lubersizers today don't remove any lead, it just moves it. Normally the excess alloy is moves the direction the bullet is sized. Nose first moves metal towards the base and base first sizing moves the metal forward towards the nose. But this movement is really a moot point as the actual movement is very little. I have sized bullets down .008" and the noticeable difference was narrower lube groove and crimp groove...