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Posted: 2/22/2010 6:37:56 PM EDT
| Has anyone ever noticed that some head stamps seem to size different than others? Case in point I am sizing and trimming some .223 brass now and I am having problems with some that seems to be still too long in the gauge after sizing. PPI and LC head stamps seem to be the culprits. I will have to run these through the sizing die again. R-P and PMC and Winchester do not seem to have this problem. Any idea why this would occur? |
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Welcome to bottle neck cases! They are a PITA..
You'll find that every brand will resize different. Every time you reload the same cases they will resize differently. The best thing to do is try to stick with the same brand cases, like LC, Winchester or R-P. Trying to process all different kinds of brass at the same time will cause a nightmare for you! -Masta |
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Different cases made with slightly different brass give slightly different results.
When I'm sizing a batch, I gauge a couple at the start and the finish to make sure they are GTG. Seldom have I had to readjust my sizing die. But it happens. Once the cases have been fired in your rifles chamber, sizing is easier to do. |
| I notice the biggest differences when it comes to cases fired in different guns. Especially where military chambers are concerned. Military chambers are more sloppy than commercial chambers for various reasons. I don't ever remember having to adjust the dies to make a different make of case fired in a different rifle though. Some do size harder than others do though so be sure to use enough, but not too much, lube. This one factor will make a big difference. |
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I notice the biggest differences when it comes to cases fired in different guns. Especially where military chambers are concerned. Military chambers are more sloppy than commercial chambers for various reasons. I don't ever remember having to adjust the dies to make a different make of case fired in a different rifle though. Some do size harder than others do though so be sure to use enough, but not too much, lube. This one factor will make a big difference. Sir, to get to the heart of the problem the OP poses you have to isolate the variables. While it's generally true that military firearms have chambers often at the high end of the applicable tolerances, military brass also is generally a bit heavier and has thicker case walls. This variation particulary comparing commercial brass to surplus military brass is really the heart of the variation of resized dimensions often encountered by the reloader. In my experience I sort all my brass and work with only one type or head stamp at a time. That is to say I set up my resizing dies to set back the case shoulder .003" less than the case dimension when the case was fired in my rifle (I use an RCBS case mic for the purpose). For bottleneck rifle cartridges such as .223 Rem. given thicker case necks it is not uncommon for those that use resizing dies fitted with a decapping assembly that includes a case neck expander ball to experience some case neck distortion when the decapping assembly and expander ball are withdrawn from the case interior. The friction of withdrawing the expander ball given the relative dimensional differences between the case neck ID and the expander ball OD can be sufficient to cause the case neck and shoulder to become distorted from the dimension you set when you adjusted your resizing die. That's why some reloaders don't use expander balls, others may lube the case neck interior, some will polish or reduce the OD of the expander ball, and others will replace the expander ball with a carbide expander ball. I lube case neck interiors and use a carbide expander ball. Regardless the method employed the goal is to eliminate case shoulder distortion due to use of an expander ball while ensuring adequate, but not excessive case neck bullet tension. HTH, 7zero1. |
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I notice the biggest differences when it comes to cases fired in different guns. Especially where military chambers are concerned. Military chambers are more sloppy than commercial chambers for various reasons. I don't ever remember having to adjust the dies to make a different make of case fired in a different rifle though. Some do size harder than others do though so be sure to use enough, but not too much, lube. This one factor will make a big difference. Sir, to get to the heart of the problem the OP poses you have to isolate the variables. While it's generally true that military firearms have chambers often at the high end of the applicable tolerances, military brass also is generally a bit heavier and has thicker case walls. This variation particulary comparing commercial brass to surplus military brass is really the heart of the variation of resized dimensions often encountered by the reloader. In my experience I sort all my brass and work with only one type or head stamp at a time. That is to say I set up my resizing dies to set back the case shoulder .003" less than the case dimension when the case was fired in my rifle (I use an RCBS case mic for the purpose). For bottleneck rifle cartridges such as .223 Rem. given thicker case necks it is not uncommon for those that use resizing dies fitted with a decapping assembly that includes a case neck expander ball to experience some case neck distortion when the decapping assembly and expander ball are withdrawn from the case interior. The friction of withdrawing the expander ball given the relative dimensional differences between the case neck ID and the expander ball OD can be sufficient to cause the case neck and shoulder to become distorted from the dimension you set when you adjusted your resizing die. That's why some reloaders don't use expander balls, others may lube the case neck interior, some will polish or reduce the OD of the expander ball, and others will replace the expander ball with a carbide expander ball. I lube case neck interiors and use a carbide expander ball. Regardless the method employed the goal is to eliminate case shoulder distortion due to use of an expander ball while ensuring adequate, but not excessive case neck bullet tension. HTH, 7zero1. Sorry you seem to have such problems. It all seems to work just fine for me. Proper lube techniques alleviate friction just as the poster above states and I believe I mentioned the same thing. Checking the size of the expander ball never hurts or getting a die with an elliptical expander is even better. |
| If you're using a drop-in style guage, the problem might just be the rims being distorted or dinged. I had a bunch of trouble getting LC brass to drop in, even though it was sized at the same time as commercial brass that went in with no problems. Turned out the rims were banged up a bit from extraction and they were just out-of-round enough that they wouldn't go in, although they were sized properly. |
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. . . military brass also is generally a bit heavier and has thicker case walls. . . With regard to 5.56mm/.223 this is just another internet myth. http://www.box.net/shared/static/eeig0a9r3c.jpg He's still shooting M-1A's, I think. Maybe even 1903's. 
owtlaw We always have to be ready to make adjustments to accomodate whatever our components (and equipment) require. You've found that all brass is not made the same - the alloy may be different, the case thickness may be different, even the distribution of the case wall thickness may be different, rims, or any other dimension, plus the cases aren't annealed the same. |
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