Case wall thickness gauge

jmorris · Nov 16, 2016

Well, the doctors didn't kill me last week and I got tired of laying and sitting so I did a few minutes of resting out in the shop today. Not a big project but an easy one I had been intending to do when I had a few min.

It's just a 3/16 rod with a .100" bearing embedded into one end that can line up with a dial indicator. I built it to mount on the backstop dowel of my runout gauge to keep it simple. Now I can have an accurate measurement of case walls without having to ruin one.

Sectioned .223 case.

Empty

300 win mag

243winxb · Nov 16, 2016

Will it measure necks?

jmorris · Nov 16, 2016

Yes, you can slide the case back and forth and measure any point.

Bart B. · Nov 16, 2016

Left picture shows thick side of once fired case; right picture's the opposite side. Measured several out of 200 and the thinnest part of the case wall was at the high point on that "pressure ring." Cases with pressure rings the same height were very uniform in thickness all the way around. I quit measuring pressure ring wall thickness long before this test but wanted to get a percentage on these Rem 308 BR cases; 20 were too uneven.

Thinnest point on neck wall is in line with that of the pressure ring high point.

The place opposite the raised point is not where the case body rested against the chamber wall; a popular myth.

Case wall thickness gauge

jmorris

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243winxb

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jmorris

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Bart B.

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