M&P40 shooting 9mm, it can be done!

[Miraclejoe]

No, not a good idea, but it did work:

A series of mistakes led to my wife's .40 S&W pistol shooting a few rounds of 9mm.

The pistol, surprisingly, still works just fine. One of the casing shows a blown primer and the other two that were saved show pressure signs. Rounds were Winchester.

Emily was not happy and has vowed never to let anyone else use her pistol...

Edit: Title of the thread changed to avoid further confusion.

 

[--Terry--]

After seeing the title only I thought you were saying the WWII German submachinegun firing 9mm. I thought "why can't it?"

Now I know that you meant M&P.

 

[Recce21]

After seeing the title only I thought you were saying the WWII German submachinegun firing 9mm. I thought "why can't it?"

Now I know that you meant M&P.

X2.

Confusing.

 

[Ar180shooter]

After seeing the title only I thought you were saying the WWII German submachinegun firing 9mm. I thought "why can't it?"

Now I know that you meant M&P.

Yah, I was confused too. My first thoughts were "Wait, the MP40 was designed to shoot 9mm, and it should be in the Milsurp forum!"

Anyways, I'm glad that both the pistol and whoever was shooting it are unharmed. I'm surprised that it didn't jam after the first shot (or did it?).

 

[Grizzlypeg]

So the 40/357 sig magazine holds and feeds 9mm properly? Good to know if I buy a 9mm conversion barrel.

 

[eigenvector]

So the 40/357 sig magazine holds and feeds 9mm properly? Good to know if I buy a 9mm conversion barrel.

The .40S&W mags work perfectly in my M&P9.

 

[Grizzlypeg]

The .40S&W mags work perfectly in my M&P9.

And they feed 9mm fine? How many rounds of 9mm can you fit in one? I'm thinking of getting a Storm Lake 9mm barrel for my M&P 40.

 

[scjordan]

Not a great idea......I had a recruit load by mistake a 9mm in a 40 cal M&P. The round fired alright but the case stayed put! The next round that chambered pushed the spent case that had lost it's rim further in the barrel. The next round fired and the projectile pushed the 9mm case half way down the barrel and we have a squib....

Greatfull that that is all that happened...

Jordy

 

[gallen270]

wow, looks like a recipe for disaster if one of those cases got pushed into the throat instead of eject. follow with another round, and there goes your wifes pistol.

kinda neat how they partially formed though.

 

[misanthropist]

looks like you haven't quite got the whole "fireforming .357SIG" down yet...

 

[curtmg]

40 necked to 9mm, is 357 sig. What do you call 9mm blown to 40? Miraclejoe .40?

They're fireformed now, just size them with your 40 dies, and load away, the wildest cat this side of ackley

 

[Miraclejoe]

What do you call 9mm blown to 40? Miraclejoe .40?

.40 Frenchy (Forty Frenchy)

(I want to make clear that I had nothing to do with the event.)

 

[NAA]

looks like you haven't quite got the whole "fireforming .357SIG" down yet...

...lol...

Now that one was good for making my tea come out my nose!

NAA.

 

[dangertree]

One of the casing shows a blown primer and the other two that were saved show pressure signs.

Quoted for understatement of the year. They look like they're dripping off the case.

It works though. 9mm is cheaper than 40 too. Hmmm.... Interesting.

 

[pitdogboy]

I may have done that by error in my G22...100% my bad. Scared the poo outta me. I promptly sold all my 9mm guns.

 

[Kindly Old Coach]

Good luck resizing those.

 

[mudgunner49]

I shoot 9 in my M&P40 all the time - never thought to try it without the 9 barrel though...

 

[Chuckbuster]

Years ago, I watched a guy shoot 9mm out of his Smith 4006. He did it every once in a while as a stunt. I can't recall what his brass looked like, but he didn't have any problems with the gun either during or after the event. However, we all thought it was risky even back then when we were considerably younger and immortal (or so we thought).