Push thru sizer questions

[Dman75]

I’ve got a Marlin 1894 44 mag that I slugged the bore. My slug measures .4315 - .432.
I ordered a Lee push thru sizer at .430 knowing I’d be opening it up to properly size pc boolits for the Marlin. I can measure and size some boolits as I go until I get .433. My question is should I use the actual slug I pushed thru and drop it in the sizer until it just passes thru then finish polishing to get the extra .001 over bore? Kinda using the slug as a go/no go gage.

[wmitty]

Since you are using a mike to measure the groove diameter, why not just measure the boolit diameter after it goes thru the sizer? Your lapping the sizer will go pretty fast if you use fine grit valve lapping compound and roll your boolits in it to imbed the grit in the sides of the slug. Just run them thru the sizer and then check diameter of a clean boolit until you open it up to where you want it. Wait a minute; I just saw that you are powder coating the boolits. I see now what you are asking and I don't know the answer, as I don't pc. I thought (initially) that you were looking for a finished diameter of .433" on the boolit. Welcome to the forum!

[Dman75]

I’m fine with measuring and testing diameters as I lap the die. I was just thinking that since I had the slug it could be used as my gage. Using the actual slug I thought maybe a more custom fit. Probably doesn’t matter since I can measure. Maybe for someone that doesn’t have a mic it would be of more use.

[gzig5]

You will be way too loose on the diameter before the barrel sized slug "drops" through the lapped die. If you had a hardened gage pin, that might work. But trying as you go is the most accurate way, IMO.

[Sam Sackett]

I agree with gzig5. Start lapping the die and periodically run a fresh bullet through to verify diameter. You will want to end up 1 or 2 thousandths over the slugged diameter anyway.

Sam Sackett.