I have a full size .357 Sig M&P.

I have read that if I buy a Storm Lake 9mm conversion bbl and some 9mm mags, I can now shoot 9mm.

True????

I have a full size .357 Sig M&P.

I have read that if I buy a Storm Lake 9mm conversion bbl and some 9mm mags, I can now shoot 9mm.

True????

I'm glad you asked. I've been looking into doing the same thing with my 40.

I'd love someone to pipe in with confirmation on how well it works. I haven't read anything how it's not possible, but the sellers of these barrels aren't describing them as conversion kits -- just "drop in barrels", which makes me a little nervous. If it doesn't work in my M&P, that's one expense 9mm drinking straw otherwise.

Wouldn't it be safer, and almost cheaper to buy a new 9mm M&P? Not being anymore of a jerk than usual - I want to know. Thanks!

I thought about this.

Storm Lake drop in conversion bbl $160.00
Three mags $90.00?

About $250.00 to convert. But then you have THREE guns...9mm, 40 and 357.

Yes.

The barrel cost 67 here: http://www.midwayusa.com/eproductpag...eitemid=730659 -- although I'm a little worried that I'll be adding to the back order list by posting this, but I guess Midway USA is anything but a secret.

I could live with a couple 10-rounders. I just wanna save some money and shoot 9mm. My shooting club thinks they're California anyway, by limiting us to 10 rounds of shooting at a time.

Anyway, at an extra 4 bucks a box, I'd have the whole conversion paid up in no time -- that is if I could still get 9mm at Walley World. Our state is getting awful low on 9mm.

The big question remain though: Has anyone ever really done it?

The problem is that the cases have different base diameters:

9mm - .392
.357 Sig- .425

Changing from .40 S&W to .357 Sig is no problem - at least in the Glock. Just drop in the appropriate barrel, and you're ready to go!

Marvin, that link is for a S&W factory 9mm Compact barrel, the factory barrels are cheaper than the Storm Lake barrels and they do not have a 9mm conversion barrel available. More important here, you cannot put a factory 9mm barrel in a 40 or 357 and shoot it safely. The main feature of a conversion barrel is the barrel hood is wider to fill the gap in the breechface that would be left by just putting a 9mm barrel in it.

It works the same with the M&P.

No. The breech face is different on the two cartridges. The .357 SIG and the .40 S&W have the same breech face dimensions, but 9mm is different.

Evidently you guys are missing the "conversion" part, refer to my post above about the breechface dimensions.

Okay, point well taken Ken. Thank you for your direction.

Sorry to beat this up for clarity, but are you saying that the storm lake barrels will work because the hood is good for the 40 to 9mm conversion?

That is what a conversion bbl is. It is not just dropping a std 9mm bbl in the gun.

As army said, that is correct.