How do you measure?

[crabo]

When you are slugging your barrel and measuring, what is your proceedure for doing it? I used some LBT push through slugs on my PC S&W .44 mag. I was firelapping it and trying to figure out what sizing die to get. The uneven number of lands and grooves makes it hard to figure out.

Veral Smith says you need a fixture to do it. Do you need a fixture or what is the technique to measure your push through slug or sinker?

Thanks,

Crabo

[The Double D]

Use the old millwright trick of rolling them between the slack jaws of your calipers. Do it several times and you will see a repeat measurement each time you do it. Thats the number you are looking for.

Had a guy on one of the boards , think this one, challenge me on this. He set up the blocks and got the same measurments. It works

[VTDW]

Double D is right. If your lands and grooves are even in number the caliper is good. If they are odd in number a mic is better but very hard to to. Roll baby roll.

Dave

[Char-Gar]

I agree with Double D. There is one place on the slugs from these SMith and Wesson 5 groove barrels that will give an accurate measurment of the goove diameter. I use a micrometer and slowly open the jaws while roatating the slug until there is just a slight feel when the widest places on the slug passes through the jaws.

It take a little practice, but a very fine measurment can be made this way.

[Ricochet]

You can also wrap around a piece of fairly stiff but flexible plastic or thin metal tape, measure it and subtract twice the thickness of the tape. Or wrap and measure circumference.