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Post by dovehunter on Nov 11, 2011 12:55:22 GMT -5
Whenever I get back from the range, after inspecting, resizing, and mouth-flaring my straight wall handgun cases, I always check the case lengths. I set my calipers to the maximum length and, if they fit between the jaws, I figure they don't need to be trimmed. Come to think of it, I don't recall ever having to trim a straight wall cases, whereas with bottle-necked cases I usually have to trim after 2-3 firings. Is it normal not to have to trim straight wall cases? Do they usually not stretch upon firing? If so, am I just wasting my time?  |
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Post by Jack on Nov 11, 2011 13:08:47 GMT -5
I haven't seen straight wall pistol cases stretch any. I think bottle neck cases stretch, at least partly, from the expander button on the decapping rod.
Anyway, I do usually check case length when I get a new batch of cases, to make sure they're all close enough in length so that they will give a uniform crimp. That really pertains to revolver cartridges, but I do it for autoloader cartridges, too. Once the batch of cases has been checked, I don't bother to do it again.
So, I guess my answer is: yes, you're wasting your time.
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bounce
Royal Member
Posts: 5,727
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Post by bounce on Nov 11, 2011 19:30:22 GMT -5
I have never trimed any once they are sized.
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Post by twomoons on Nov 11, 2011 22:45:53 GMT -5
Straigh walled cases don't leagthen much if any during firing. I think most case streching occurs during sizing whan the expander plug pulls out of the neck. For example when you size 30-30 with the long neck if you lube the inside of the neck good you get bvery little lengthening but if you don't lube they need trimming every other reload. I lube inside and out and size and then clean the cases and finish reloading and I do a LOT less trimming then I use to.
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Post by dovehunter on Dec 27, 2011 17:37:51 GMT -5
I finally found a straight-wall case that needed to be trimmed. It was a Win. 9mm Luger case I picked up at the range. It was obviously a once-fired case too. I think I'll keep on checking the length of my cases. It doesn't take that long and, as someone once told me: there's no substitute for knowing.
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Post by Jack on Dec 27, 2011 23:52:03 GMT -5
I'm really surprised you found a 9 that was over length.
Years ago I measured a couple thousand 9mm cases, trying to find one that was too long. Off the top of my head, I think the figure of merit is .754. Haven't checked, so I could be wrong. Anyway, I didn't find a single case that was over length.
The reason I did all that measuring was because I got curious as to whether 9's (and other straight wall pistol cartridges) really headspace on the case mouth. Answer? Nope, they don't. Between the extractor holding the rim, and the bullet potentially touching the barrel throat, that's what really headspaces a 9mm cartridge. At least in every 9mm pistol I've ever messed with.
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