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Measuring Neck Wall Thickness

danny

Silver $$ Contributor
Some time ago, one of the earlier times when components were scarce, I started to make some .22-250 brass from .308W. At some point, I am going to have to measure the case necks and turn them. I have a Forster Co-Ax Case and Cartridge Inspector, which is said to be able to measure neck wall thickness, but it uses a dial indicator. I also have a Neco unit, which may also do the same. I did not check if it does, but it also uses a dial indicator. I have seen units such as this "Brownells" (formerly Sinclair International) Case Neck Wall Thickness Micrometers.


Which is the best way to measure? I am thinking the direct reading micrometer style tools vs. any of the units I have, or any other utilizing an indicator, but I am not really sure. The simplest and cheapest would be using what I have, but I also want to do it the best way.

Danny
 
I had Lester Bruno's son-inlaw turn some 6BR necks for me at $1.00 apiece. I wanted them perfect. When I got them a friend who is a retired areospace machinest wanted to check them and said the only way to correctly get an accurate measurment within .00005 is with a ball micrometer. He said the necks were the most consistant ones he's ever checked.
 
Not trying to derail your thought, but I have had good luck and a lot less work making .22-250 from 6 and 6.5 Creedmoor brass. One pass in a standard FL die works for me. No neck turning needed with a standard chamber, only about .040 to trim off. I've made 150 in the last few months from once fired range pickup brass.

I have the #220 Starrett multi anvil micrometer for the times I do turn necks. I made the hardened .175 dia. ball stem, adjusted the thimble to read zero when closed on the ball. You can substitute a 1/16" dia. and up dowel pin.
 

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Your current tools may be fine. If you're looking for an alternative, I have used this, and still do:


Amazon say out of stock but if you're interested there are other suppliers
Thanks. My problem with the tools that I have are that they use a neck pilot. The pilot may, in some cases, not touch the inside of the case neck, so in effect, using an indicator, you are just measuring the distance from the pilot OD to the case neck OD, which could be measuring some amount of gap, or at other points, the fit could be perfect, and it would work better. If I am correct on how these units "measure", then, I think that it might not be the best method.

Danny
 
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Not trying to derail your thought, but I have had good luck and a lot less work making .22-250 from 6 and 6.5 Creedmoor brass. One pass in a standard FL die works for me. No neck turning needed with a standard chamber, only about .040 to trim off. I've made 150 in the last few months from once fired range pickup brass.

I have a Starrett ball micrometer for the times I do turn necks.
You are correct, but at that time, the brass you mention was probably no more available than .22-250 itself, and maybe even less available. I had extra .308 at the time. Sometimes you have to work with what you have, or can get, not what makes the best or simplest solution.

Danny
 
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Some time ago, one of the earlier times when components were scarce, I started to make some .22-250 brass from .308W. At some point, I am going to have to measure the case necks and turn them. I have a Forster Co-Ax Case and Cartridge Inspector, which is said to be able to measure neck wall thickness, but it uses a dial indicator. I also have a Neco unit, which may also do the same. I did not check if it does, but it also uses a dial indicator. I have seen units such as this "Brownells" (formerly Sinclair International) Case Neck Wall Thickness Micrometers.


Which is the best way to measure? I am thinking the direct reading micrometer style tools vs. any of the units I have, or any other utilizing an indicator, but I am not really sure. The simplest and cheapest would be using what I have, but I also want to do it the best way.

Danny
These tools area just find for measuring neck wall uniformity, but not for measuring "neck wall thickness". If you want a good measurement of neck wall thickness, you really need to us a micrometer, like this one:


Not only can you measure neck wall thickness with this, but I find I don't really need those other uniformity tools to check consistency as this can do it too.
 
The Sinclair/Brownells unit seems like the nicest unit, having a stand, but it is a non-digital unit. I can read a non-digital unit no problem and usually prefer them, but the iGaging looks like a lot of tool for the money, and it is digital, which should be a lot faster, a big plus. It just lacks a stand and is a lot cheaper. Possibly, I could buy, or even make micrometer later if I could not live without it.

Danny
 
These tools area just find for measuring neck wall uniformity, but not for measuring "neck wall thickness". If you want a good measurement of neck wall thickness, you really need to us a micrometer, like this one:


Not only can you measure neck wall thickness with this, but I find I don't really need those other uniformity tools to check consistency as this can do it too.
I think that you are correct, and I needed to hear some opinions on this. One probably does need the micrometer to measure the case directly. With the dial indicator units, you could probably zero on the pilot, put the case on, then "measure" the thickness, but it is not a direct measurement, and probably not the most accurate way to do it.

Danny
 
This is the ball micrometer that I use. does well for me and it did find a problem with my lapua 6br brass that i did not see without it.
https://www.amazon.com/Anytime-Tool...eywords=ball+micrometer&qid=1644113310&sr=8-4
I bought a micrometer that is probably of the same make, and while it works ok, the measuring lines were very light and did not seem really substantial. Also, some of the lines were slightly off when I zeroed it. I got it set and figured out its quirks.

Danny
 
The Hornady, (post #8), which might be made by Mititoyo, is good because of the narrow spindle, giving you a better single point contact On the outside.
 
I think that you are correct, and I needed to hear some opinions on this. One probably does need the micrometer to measure the case directly. With the dial indicator units, you could probably zero on the pilot, put the case on, then "measure" the thickness, but it is not a direct measurement, and probably not the most accurate way to do it.

Danny
I use a micrometer like dhagerty40 showed in his post above and it has worked well for me, except . . . it's design doesn't allow me to get as close to the neck-shoulder junction as I would like and this Hornady one does better for that, but I make do.

Oh, and yes . . . it'd best used when you have a stand, which you'd have to buy in addition to it.
 
These tools area just find for measuring neck wall uniformity, but not for measuring "neck wall thickness". If you want a good measurement of neck wall thickness, you really need to us a micrometer, like this one:


Not only can you measure neck wall thickness with this, but I find I don't really need those other uniformity tools to check consistency as this can do it too.
Will that work on .17 cases?

Danny
 
.17 cal is just a Pain in the you know what! I measured the size of the ball on mine and it measures .182" which I think is the same for the hornady.

this is the only one I know is designed for measuring .17 Cal: https://www.midwayusa.com/product/1012725281?pid=134296
Thanks for the help. I think that I am going to need one that will also work for .17. It seems like the Sinclair/Brownells also works on .17. It has a stand, for not a lot more.

Danny
 
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Once you get some brass measured with the tube micrometer, later on down the road you should also compare the diameter over the neck with the bullet seated using a standard micrometer.

That over the seated bullet diameter is smoother and less noisy and should come close to the bullet diameter plus two times the neck thickness.

The surface roughness and waviness of the cut on the brass can make the individual tube mic measurements noisy and a challenge so it is good to play with both measurement styles to see how they match.
 

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