Troubleshooting: diagnose magazine jams
This is a discussion on Troubleshooting: diagnose magazine jams within the Defensive Carry Guns forums, part of the Defensive Carry Discussions category; I need help diagnosing what, specifically, is wrong: Three out of eight of my magazines for the Browning BDM 9mm are jamming regularly and reliably. ...
October 10th, 2006 09:30 AM
Troubleshooting: diagnose magazine jams
I need help diagnosing what, specifically, is wrong: Three out of eight of my magazines for the Browning BDM 9mm are jamming regularly and reliably. The other five are fine. I need to find out what's wrong and correct it. I have marked these three and put them aside until the solution is found.
- Gun: Browning BDM 9mm semi-auto.
- Magazines: Factory 15rd.
- Mag springs: Factory weight Wolff springs, and relatively fresh with only ~1000 rounds on them (all).
- Recoil spring: Factory weight Wolff springs, given that I'm shooting mid-power range rounds right now. The +1lb and +2lb Wolff springs will go in once I have broken in the gun and am starting to evaluate hotter factory loads.
- Problem occurs when: magazine is full, one short of full, or half-full. Doesn't seem to matter. And, only with these three magazines. The others are just fine.
Jams that have been experienced, recently:
- Almost always, the jam almost appears to be a double-feed. The top bullet will be nose-up and jammed up against the hood of the barrel, with the second bullet looking like it has halfway come out and jammed up beneath the first bullet.
- Half the time, simple racking of the slide frees everything up. Half the time, it's seriously jammed up, requiring locking back of the slide, praying to JM Browning, swearing, and ripping out the magazine.
- In 3/500 rounds or so, a casing fails to eject after firing, remaining in the barrel and the next round wedges in behind it. (Those are fun to clear.) I understand that this is likely a symptom of a completely different problem.
Suggestions? Magazine feed "lips" need tuning, to eliminate the severe nose-up condition? Magazine and/or recoil springs need replacement with different weight springs? Throating/polishing?, but then the other 5 mags have no similar problems. Breech face and/or extractor are rough and need polishing/tuning?
Last edited by ccw9mm; October 10th, 2006 at 10:10 AM.
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October 10th, 2006 11:05 AM
Your major problem seems to be the occasional double feed from 3 of your 8 magazines. I would guess that this results from the feed lips at the top of these three magazines being "too open", such that the round can pop upwards out of the magazine before the end of the bullet is sufficiently far into the chamber to restrain its upward motion.
You might be able to confirm this by very careful measurement, if you have the ability to measure the gap between the feed lips to the thousandth of an inch. I would bet that the 5 good magazines have a smaller gap than the 3 bad magazines.
The two solutions that come to mind would be to attempt to bend the feed lips slightly inward to close the gap on the 3 bad magazines, or to simply discard the bad magazines since you have 5 good ones you can use. I would salvage the springs and followers, and perhaps the base plates if you do this - maybe you can use them in the future.
Last edited by pogo2; October 10th, 2006 at 01:39 PM.
October 10th, 2006 01:22 PM
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