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case trimming
Muskrat30 is right on regarding trimming 25ACP cases. Straight wall cases for semi-autos headspace on the case mouth and loaded rounds should be taper crimped to take out the case mouth flare (bell). Several years ago, I decided to trim some once-fired 40S&W cases to the same length and found that they were under the recommended trim-to length in data books. Then I checked some new, unfired cases and found the same thing.
Ive written to several "experts" and have received different recommendations. One said to sort the cases by length and trim as necessary -- but he didn't say what to do with those that were too short. Another recommended trimming to the length of the shortest cases in the lot.
If a case is much too short, the firing pin might not strike hard enough to ignite the primer. If way too long, the slide might not fully engage. Long story short, I just forget about case lengths with all my semi-autos and have never had a problem. I have loaded for 9mm, 40S&W and 45ACP. Roll-crimping is not advisable with the semi-auto cases, and the taper crimp works fine for me.
270man
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