Forums / Gun Discussion / Case Length Differences

5 years 36 weeks ago, 2:48 PM

runawaygun762

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So I was prepping a bunch of my 9mm cases for reloading and realized that even after sizing, there is a variation in case lengths. I had cases, sized in the same press with the same die (Lee O-press and carbide dies) that varied from .0742" to .0753". For anyone who has reloaded for a while, does this sound significant? I have separated them by length and will keep everything else the same when I load them up to see if there is a noticeable difference in velocity or accuracy. When using larger calibers with larger cases, variables like these are much less important, but when you're dealing with a cartridge that has a starting powder charge of less than 5 grains of some types of powders, small variables become more pronounced.

"I have always been a soldier. I have known no other life. The calling of arms, I have followed from boyhood. I have never sought another." From The Virtues of War, by Steven Pressfield.
5 years 36 weeks ago, 4:58 PM

fordvg

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runawaygun

I never checked the length of my brass when I was shooting 45 acp in IPSC matches.

"WAR IS A RACKET, I spent most of my time being a high-class muscle-man for Big Business, for Wall Street, and for the Bankers." Major-General Smedley Darlington Butler USMC Ret. 2 time Medal of Honor winner.
5 years 36 weeks ago, 5:21 PM

runawaygun762

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fordvg

Most of mine are .747", and I've separated them by thousandths of an inch and when I go shooting in Tucson on Tuesday morning, I'm going to have a bunch loaded up to shoot over the chrono and then print some groups. With the same OAL and different case lengths, that'll mean some bullets are going to be seated slightly deeper and the pressure differences will make for slightly higher or lower velocities. I'll test and report, roger out.

"I have always been a soldier. I have known no other life. The calling of arms, I have followed from boyhood. I have never sought another." From The Virtues of War, by Steven Pressfield.
5 years 36 weeks ago, 6:14 PM

fordvg

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Ok, runawaygun

Yes, they will have different pressure. Let me know what you find out I don't think it will be much,but I could be wrong. LOL

"WAR IS A RACKET, I spent most of my time being a high-class muscle-man for Big Business, for Wall Street, and for the Bankers." Major-General Smedley Darlington Butler USMC Ret. 2 time Medal of Honor winner.

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