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Republican!!!
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I've been having some problems getting the crimp just right on my 9mm loads. I think this article does a good job of explaining my issue. I'm using a Dillon Precision SDB progressive press and I believe I'm just slightly over-crimping on some loads.

Here's the article:

Squeeze Play: How to Properly Crimp Ammunition - Handguns

PS - if people have problems reading it, I'll cut and paste it into a post.
 

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Retired Moderator & Gunsmith
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jlh820, That's a very good article ... should be required reading for anyone that reloads.
 

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Republican!!!
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Discussion Starter #6
Thanks, everyone. I hadn't seen the topic covered much, but it was a problem with my first batch of 9mm. I suspected mine were a little over crimped, but I measured the casings according to my Lyman book and they were within specification. However, they were occassionally not feeding; worse on some guns than others.
 

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Good article. Checked recent .45 reloads. Apparently, I got it right. Just need to increase powder loads for a little more velocity for function reliability.
 

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Nicely written article; thanks for posting it. It will help a number of folks...
 

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Hate to tell y'all, but this isn't news. I've been recommending the procedure for many moons. Please actually measure case wall thickness at the casemouth because there is no norm. IMO, Winchester is the most consistent brand of brass but you're likely to get .012" thickness at the casemouth with either 9mm or .45 ACP. Multiply that by 2 and add bullet diameter. If you're loading 9mm, subtract .0015" for crimp, for .40 S&W or .45 ACP, subtract .002" for crimp. ;)
 

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When I first started loading for 9mm I had a couple hundred rounds that would keyhole at 25 yards out of a P-85 and a CZ-75. I fussed and fumed and blamed those darned cast lead bullets. Sometime later I got the bright idea to check my crimp and it turned our I was literally CRUSHING the bullets at the crimp groove. Backing off to a lighter crimp did the deed and I had a pretty nice tight grouping load.

My subsequent experience with the 9mm has shown me that a minimal taper crimp works best for my loads.
 

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I can't read the damn thing. It keeps resizing itself constantly. The article jumps in several steps from about 3" wide to full window width at about 3 second intervals.
Taper crimp--run your finger down the bullet ogive to the case mouth. If the mouth feels like it is sticking out, you need more crimp.
If your finger can't feel the case mouth, you have too much.
If there is a very slight shiny ring around the case mouth, the crimp is probably just right.
If you hold the case up against a well-lit white backgroud, you can see if the case mouth is still belled or not. If you make small adjustments, you can see when the case mouth is straight--that is all the "crimp" you need.
If you have a case drawing and enjoy trying to measure the case mouth OD, then take the case mouth dimension and crimp to that dimension or 0.001" less.
If you sit around and worry about it, you might have other issues.
 

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Crimping was my final weakness after I got over the priming issues and finally bought a decent powder weighing system. I could not get it right with the RCBS system that seats the bullet and crimps at the same time. So I finally was told of the Lee crimping die, that only crimps. After I tried one, I had to buy one for all the calibers I load (6). It does make an extra step, but has relieved all my headaches about crimping. I never have roll crimped, someday I may find a need to, but for now the Lee die is a God sent. Usually I just feel a factory load with my fingers and attempt to taper crimp mine the same way, seems to work fine. If I'm happy with my reloading I do it more often.
 

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Now I just got my 9mm reloading stuff (wife got the annual gun this year but that's ok, I shoot a SBH in 44 mag and it's her turn) but no primers yet (supposed to get here on Monday, had to order (gasp) match primers, nothing else left anywhere!). So I haven't done anything but resize, cast boolits, flare, etc. But I will tell you for a fact that if you don't "overcrimp" your 44 mag cast boolits, especially with what I use (Lee RFN 310 cut with enough pewter and lino to lower them down to 300 g and then gas checked, in front of 21.5 g H-110, yikes!), they will start to slide around in the case after a few shots. And they shoot quite well "overcrimped" thank you - 3 MOA at 100 yds off a rest and MOD (or Elk or Bear) at up to 100 yards every time leaning the barrel up against a tree or anything else handy.

Now I don't know how the 9mm will behave, except with the box of cheap ammo we got free with the SR9, which we already shot up, but to me it seemed like shooting my .22 single action, and my wife (after several years shooting reduced loads in my SBH) said "this doesn't kick at all, but I sure had better wear my glasses and not wear anything low cut (the brass comes straight back and very hot!). So perhaps I should approach this little round with less of a brute force attitude.

Anyway, I use Lee crimping dies for all the rifles and pistols I load for, and I do it pretty much by feel, which, now that I read that article, is basically not so much that you deform something, and not so little that the boolit comes loose or the case hangs up in the chamber. All this seems intuitive to me, but then that's what 40 years of doing this stuff almost every day does to you. Anyway, if that helps, great, if you haven't been having any problems, great too. Win-win either way so thanks for the article.
 
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