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9mm in .40/.357 magazines

2609 Views 13 Replies 8 Participants Last post by  ysued
There was a thread a few weeks back that mentioned the possibility of loading 9mm into .40/.357 magazines, specifically that a S&W rep did this to demonstrate reliability.



Anyway, I just got some of the 10-round .40/.357 magazines, and while they hold 12 rounds of 9mm, the span of the magazine lips won't hold 9mm cartridges reliably. They pop out far too easily, at least for my comfort. While this trick may be fine for demonstrations, I woud not do this on a regular basis.



Interestingly, the "load 9mm into .40 Auto magazines" trick works well for 10-round HK USP40 Compact magazines, and hold 13 rounds.
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Interesting. I too experiment with mags/cartridges, etc. Funny how some magazines will work when "crossbreeding", while some won't...but most feed their parent cartridges just fine...
I wish the 9MM mags would not even fit in the .40s and vise versa.
BSTOCK said:
I wish the 9MM mags would not even fit in the .40s and vise versa.


This is the reason I will not buy a 9MM version of the M&P. My luck I would grab the 40 and the 9MM mags on the day I would actually need to use it. Argh, I agree completely.
MP40Fan said:
[quote name='BSTOCK']I wish the 9MM mags would not even fit in the .40s and vise versa.


This is the reason I will not buy a 9MM version of the M&P. My luck I would grab the 40 and the 9MM mags on the day I would actually need to use it. Argh, I agree completely.[/quote]

I really like my Beretta Model 92, I like the feeling of the slide like it's on ball bearings, I thought a little about a Beretta 96, but I was afraid of exactly that, magazine confusion!



That's OK though, now I've got the MP40 and it's great!
omg scary thoughts just flashed in front of my eyes. would be dangerous and lethal to shoot a .40 out of a nine barrel
. anybody have first hand knowledge on this type of foul up?
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mad212 said:
omg scary thoughts just flashed in front of my eyes. would be dangerous and lethal to shoot a .40 out of a nine barrel
. anybody have first hand knowledge on this type of foul up?


.40 wouldn't fit into the 9s chamber so I guess you couldn't get it in battery.
What's the phrase? "The most important safety is between your ears?" I fully intend to add an M&P 9 and whatever compact versions come out as they become available. If I can't keep my magazines straight, there's something wrong, since they ARE clearly labeled.
toocool said:
What's the phrase? "The most important safety is between your ears?" I fully intend to add an M&P 9 and whatever compact versions come out as they become available. If I can't keep my magazines straight, there's something wrong, since they ARE clearly labeled.




First the compact mag probably will not fit in the full size and vice versa so you are safe there. As far as being clearly labeled, have you ever seen a M&P mag? They are black and have the cal stamped lightly on the mag body, black on black. You have to be in good light to read it. Probably be better off counting the round indicator holes that reading the cal on the mag.

The safety in my head tells me if I ever need to change mags during a stressful moment I better put some marking on one of the calibers to make sure I don't insert the wrong cal mag. When things get crazy and dark the best plans for keeping the mags separate disintegrates. That's what the safety in my head tells me.

I thought of marking the floor plate but don't want to alter the outward appearance of the mag. I think I am going to put some white permeate marker over the 9MM mag ID stamp. That way you would not notice any difference when the mag is inserted. I think I will also put a little dimple on the 9MM floor plates so I can distinguish them in the dark. Might seem a little elaborate but I see where a problem could exist and I can easily rectify it. I have four full size M&Ps, two 9s and two .40s + six mags for each pistol. Lot of chances to screw up.

BTW toocool, anyone that thinks they are immune to making a mistake needs to take extra precautions. Especially when firearms are involved.

Just my .02
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im just going to have to get a compact .40
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I just ID the different mags by a visual or tactile inspection...the 40 magazines have smooth sides, the 9mm magazines have a pair of grooves running down each side...
mbinky said:
I just ID the different mags by a visual or tactile inspection...the 40 magazines have smooth sides, the 9mm magazines have a pair of grooves running down each side...


Thats a good idea :idea: Have to do the practice in the dark drill.

Back with results of test. Although I noticed the difference in grooves I never though it would be so easy to use them for identication. Just took 5 of each cal and did the blind test. Not a problem. You got it mbinky. So simple it I overlooked it. :oops:

Thanks
mbinky said:
I just ID the different mags by a visual or tactile inspection...the 40 magazines have smooth sides, the 9mm magazines have a pair of grooves running down each side...


This is funny!!



Brownells sell M&P Magazine bodies, they say they fit all calibers 9mm, 40 & 357!!





Has anybody purchased any of these??





Y
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I answered my own question.



Brownells website is wrong, and willbe fixed today!!



The Mag Tubes and Followers they "DO" have are 40/357, not 9mm!!



They will soon carry the 9mm tubes and followers!!



Just an FYI
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