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Discussion Starter · #1 ·
So first off I apologize to the big m&p guys for my newbie ignorance with m&P's. I'm a bolt action guy and I only got this for personal projection. Now supposedly this thing has been rebuilt from the ground up and it came with a threaded 9mm barrel and a standard .40 cal barrel that I can swap and it allows me (obviously) to change rounds with ease. Now being ignorant to hand guns and their respective calibers... I bought 9mm Lugar +P+ ammo and in complete ignorance fired off two 17 round mags off. On my second purchase I received a warning that +P+ might be dangerous with my m&p. So I then researched as much as I could however, I could not get an answer to one single questions. So here it is... If my m&p can fire both 9mm Lugar and .40 cal with just a simple switch if the barrel; then is it really bad for my specific m&p to fire 9mm +p+ ammo given that it is obviously higher combustion however I am not confident that 9mm +p+ is a higher combustion than the .40 federal ammo... Any information would be greatly appreciated.
 

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It has to do with the pressures being generated by the +P+ rounds.

I believe that the M&P Manuals note the the use of +P ammo is acceptable, but will cause wear of the pistol to occur more quickly than standard pressure ammo. +P+ ammo is not recommended for use in M&P pistols.
 

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I will offer a little different opinion than most. If your 9mm barrel has good chamber support, I would not worry about it if you are only firing a box or 2 through it. I have fired Underwood +P+ 9mm which loaded very stout, through a Glock 48. Some +P+ 9mm, like the Winchester Ranger 127 Gr is not really loaded all that hot. The popular Federal 115 gr +P+ is not hot at all. I would shoot that as much as i could afford through any normal service duty 9mm. The only guns I would not shoot with it are little pocket guns like the SIG P938 or similar guns. The gun in my avatar is an M&P 40 2.0 with a KKM 357 SIG barrel in it. Full power 357 SIGs are considerably more potent loads than 9mm +P+m, even if the pressure of the SIG is slightly lower. No gun maker that I know of approves of +P+, but some police departments have used it for years. In fact, the Win Ranger +P+ was supposed to be for LE only. Bottom line is, I would shoot +P+ it in my lightweight frame S&W Model 39 or an M&P 9mm (other than the Shield) if I had one, without hesitation.
 

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Discussion Starter · #4 ·
I will offer a little different opinion than most. If your 9mm barrel has good chamber support, I would not worry about it if you are only firing a box or 2 through it. I have fired Underwood +P+ 9mm which loaded very stout, through a Glock 48. Some +P+ 9mm, like the Winchester Ranger 127 Gr is not really loaded all that hot. The popular Federal 115 gr +P+ is not hot at all. I would shoot that as much as i could afford through any normal service duty 9mm. The only guns I would not shoot with it are little pocket guns like the SIG P938 or similar guns. The gun in my avatar is an M&P 40 2.0 with a KKM 357 SIG barrel in it. Full power 357 SIGs are considerably more potent loads than 9mm +P+m, even if the pressure of the SIG is slightly lower. No gun maker that I know of approves of +P+, but some police departments have used it for years. In fact, the Win Ranger +P+ was supposed to be for LE only. Bottom line is, I would shoot +P+ it in my lightweight frame S&W Model 39 or an M&P 9mm (other than the Shield) if I had one, without hesitation.
[/Q
I got the 40 pro series. This is with the .40 barrel.
17589
 
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