What are you guys using to measure case neck wall thickness?? I have the rcbs runnout tool and it's "SUPPOSED" to do it but I can't get consistant readings off that stupid bushing.
I'm thinking about the best tool is a ball micrometer??
Do you guys run virgin brass over a mandrel first....I would think this might be must?

I use a Dial indicator with an inside caliber pivot support , like on a case trimmer .

Shoot Straight Know Your Target . ...

"I'm thinking about the best tool is a ball micrometer??"

I'm thinking you are right.

Hey kraky

I have both and it takes a little practice and perseverance but I prefer the RCBS best because it is much easier and faster.

You need to make a mark and measure with the same place on the floating collet and use your left hand to put positive pressure downwards on the collet



then raise the collet with your left hand and rotate the case with your right and remeasure. Make sure the case is level.

The ball micrometer is perhaps a touch more accurate and you can measure a lot more places on the case neck



but it's a bitch to hold steady. I think they might make a cradle for some of them, if so, get it.

Mostly I use the RCBS though.

Thanks Woods...that was a good tutorial. I think I see where I got my frustration with the rcbs.....I actually thought I could sping the case on stud and get a consistant measurement. I think what I now realize is I can spin it a 1/4 turn...measure...spin a quarter turn...measure etc etc. Trying to spin it like I would when doing neck runnout was IMPOSSIBLE. Thanks for de-dumbing me...at least on this subject. (And saving me about $40-50 on that ball mic.)

Unless you really want to measure the wall thickness on individual cases, if you just want to find the wall thickness on a batch of identical brass (assuming they are close to identical) then just press a bullet into one case and measure the OD (Outside Diameter) of the case mouth with the bullet in place.

You already know the OD of the bullet.

Subtract the bullet OD from the case mouth OD, then divide that by 2, and the answer is the wall thickness.

benchrest folks measure neck thickness all the time, its mandatory to fitting a tight necked gun.
Most use a tubing mike or something very similiar. Places like Sinclair International carry the tools, they have a web site.

The ball micrometer is the most accurate tool. It is held in the palm of the right hand with the spindle operated by the thumb and forefinger; the workpiece (brass) would be held in the left hand. With a little practice it is simple to use accurately; it isn't necessary to use the ratchet or thimble friction feature. Both Lyman and Graf offer cheap ones that should be satisfactory.

The spinner types have trouble accommodating irregularities in case shape.

Might try one of these
http://www.sinclairintl.com/cgi-bin/category.cgi?catego...m=NCG-010&type=store