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Difference of thickness of walls of brass!


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Old 11-23-2009, 06:58 PM   #11
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Default robo's right on point.

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Do not despair. Diffeences in 9mm brass are not a large issue. Segregate by brand (headstamp) and load it up. The slight differences will not make a noticeable difference in this caliber.
After segregate by head stamps, load each batch individually. Make minor adjustments to your dies when you change brands/head stamps of cases. It really will not make any difference though on your load performance. If loading cast bullets (.356" diameter) you may have to lower your expander plug slightly on the thicker wall cases??, to avoid bullet shaving. Your crimp die may need to be lowered, for proper taper crimp on the thinner walled cases? If the loads fit a 9MM case gauge, or your barrel chamber, then your good to go..


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Old 11-26-2009, 09:14 PM   #12
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I want to describe the problem graphically!
.... for the prevention, understanding errors.
Difference of thickness of walls of brass! - Ammunition & Reloading


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Old 11-27-2009, 03:35 AM   #13
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Originally Posted by iskatel View Post
I want to describe the problem graphically!
.... for the prevention, understanding errors.
Difference of thickness of walls of brass! - Ammunition & Reloading
The term here to use is case neck run out. The key word would be run out.

Definition "Run Out"-To occupy or exist in a certain range. ie: The size, or in your case,"thickness", runs from small to large.

Are you using a ball micrometer to measure this thickness variaton of the wall of your cases? Or are you using a case neck guage to measure this variation in wall thickness? Also have you chamfered the mouth of the case before making your measurements?

A vernier caliper is not the tool to do this with. Also a ball micrometer is difficult to get consistant accurate readings without practiced use of them. A case neck guage would be the way to go to make this measurement. In your situation (pistol ammo) I dont think this variation is critical.

Case neck run out over .0015 to .002" in bottle neck cartridges (rifle types) will affect accuracy, which stalking bear said could be cured by neck turning, however, I dont think this holds true for pistol ammo.

One of the better seasoned reloaders on this forum hopefully will chime in soon and address this problem of your 9mm pistol ammo run out situation, which I dont think is a problem.

I measure neck run out on my bottle neck rifle ammo and will turn the necks to correct if the run out exceedes .0015". When it comes to my rifle ammo, however, I'm a anal retentive arse. I also have lately begun reloading .44 mag for my pistol and for ****s and grins measure run out on a few of these cases with a ball micrometer and there is some run out variation from time to time which I pretty much ignore and reload.
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Old 11-27-2009, 05:04 PM   #14
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Even if you were to fire from a machine rest, I doubt you will notice the difference in accuracy. Load em and shoot em. The short sight radius of a handgun and the relatively loose tolerances (compared to a bolt action rifle) are the limiting factors that have more influence on accuracy than any amount of run out you might see.
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Old 11-27-2009, 10:06 PM   #15
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I absolutely agree with you-a vernier caliper not the tool for this measurement (his design- is not very accurate measurement (my opinion)!
No, I did not use a case neck guage.
I used a micrometer and I confident in the accuracy of measurement("Run Out" <=.0037 inch), and of course I chamfered the mouth of the case before making measurements!
...... by the way, the main question - can I normally use my brass ( shooting-standard )?!!!!
I read all the answers-brass repairs do not need !!!
I am very glad !!!)))))
All guys who helped me council, thank you very much !!!!!!
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Old 11-28-2009, 06:24 AM   #16
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Quote:
Originally Posted by iskatel View Post
I absolutely agree with you-a vernier caliper not the tool for this measurement (his design- is not very accurate measurement (my opinion)!
No, I did not use a case neck guage.
I used a micrometer and I confident in the accuracy of measurement("Run Out" <=.0037 inch), and of course I chamfered the mouth of the case before making measurements!
...... by the way, the main question - can I normally use my brass ( shooting-standard )?!!!!
I read all the answers-brass repairs do not need !!!
I am very glad !!!)))))
All guys who helped me council, thank you very much !!!!!!
Yes, for pistol, you can normally use your brass. Also a ball micrometer is a good tool to measure wall thickness if your adept with use of one. In my case, in my younger life, I had to become good at using ball micrometers, because I had to fabricate parts with much closer tollerences than required for reloading ammunition of any kind.


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