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M&P9 barrel questions

Doulish

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I recently bought a used M&P9, and decided to run a few snap caps through it to get familiar with working the action, etc. To my surprise, the slide would not close all the way. I then tried putting the "proof" brass in, and got the same result. After reading the instructions, I took the slide off, and removed the barrel. I measured from the back face of the barrel to the "step" where the brass would stop, and it's only 15.5mm deep. The top of the barrel is stamped 9mm, but no other markings. I'd like to get some more information before I bring it back to the dealer. Thanks in advance.
 

murf4321

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Dropping into chamber & then trying to close the slide won't work. Slide won't close


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Doulish

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OK. Will this help demonstrate? This is the proof brass inserted into the barrel until it stops.
DSC00263a_zps96cb4367.jpg

I can take a picture of the assembled action showing the gap where the slide won't close fully.
 
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That looks pretty normal to me.
9mm headspaces with the case mouth against the ridge in the barrel chamber.

Can you show a pic of how the slide is not closing?

Try with a snap cap or empty case in the barrel, then install the barrel in the slide off of the frame, Does the barrel lock up against the breach face?
 

Doulish

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Dropping into chamber & then trying to close the slide won't work. Slide won't close


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I see what's happening now. The rim of the case is sitting in front of the extractor, not inside it. Thanks, SJan, for your suggestion to look at it off the frame. I think I also understand what's happening, and why. I'm not letting the slide snap back hard enough to pop the extractor over the rim. I guess I need to work on that, which is why I bought the snap caps in the first place. Thanks for the help.

DSC00264a_zpsf548c779.jpg
 
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I'm not letting the slide snap back hard enough to pop the extractor over the rim.

No, don't do that
See my post #2

Load rounds (snap caps) in a magazine, insert magazine into gun, rack the slide. Don't close the slide gently, let it fly forward with all the recoil spring pressure. The round will feed up the breech face, sliding under the extractor. Snapping the extractor over the rim causes unneeded wear. It's nothing to worry about, its just not something you should get in a habit of doing.
 
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It doesn't matter if you let the extractor jump over the rim on an M&P. I've probably done it over 10k times on my EDC which has about 14k-15k rounds through it.

Let it fly.
 

Wendell

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Most firearms with a detachable box magazine were designed to be fed from the magazine.

You have already experienced an example of one of the good reasons to feed your pistol only from the magazine.

Feeding from the magazine is a best practice.
 
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Most firearms with a detachable box magazine were designed to be fed from the magazine.

You have already experienced an example of one of the good reasons to feed your pistol only from the magazine.

Feeding from the magazine is a best practice.

The only thing he experienced was limp wristing the action and how not to operate the firearm. When properly operating the slide (i.e. pulling it all the way back and letting it go) a round will never fail to chamber on a properly functioning firearm.
 
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