40 S&W to .357 Sig

[Robbins290]

When I purchased a Storm Lake 9mm conversion barrel for the M&P40 at Grabagun, the had a super offer for 9mm factory magazines. I purchased 2 of them. So I haven't tried using a 40/357 magazine with that barrel.
But now I'm curious to see if those magazines will work with the 9 next time at the range.

KC of ohio, I noticed with the M&P (full size anyways) that they need the 9mm mags. Mine will not cycle a full 17 rounds thru the mag without some kind failure to feed. I had plenty of 9mm mags so i had no issue. I had the opposite with the glock 22, ran like a sewing machine with the 40 mags.

 

[Rockrivr1]

Another Sig 229 that was converted so that it's now a true three caliber gun. It came in 40 S&W and had a 357 Sig barrel with it when I bought it. After some research I added a Barsto Drop In 9mm barrel for the 229 and all three calibers work flawlessly in the platform. I didn't need to change any springs and the 40/357 mags also reliably feed 9mm as well. Can't go wrong. I have over 2000 rounds of 9mm, over 1000 rounds of 40 S&W and roughly 500 rounds of 357 Sig through the gun and it's still running pretty flawlessly. It's one of my most accurate handguns as well. Love it.

 

[starling]

KC of ohio, I noticed with the M&P (full size anyways) that they need the 9mm mags. Mine will not cycle a full 17 rounds thru the mag without some kind failure to feed. I had plenty of 9mm mags so i had no issue. I had the opposite with the glock 22, ran like a sewing machine with the 40 mags.

Same goes for the Sigmas. The 40s&w mags will mostly work. I have have had them bind in the mag tube a few times though. Stronger mag spring helped... however......due to the slight taper of the feedlips on the 40s&w mags sometimes the 9mm will release too early from the magazine. The stronger magazine spring helped in one area and then created more problems in the other. Cannot use 9mm mags in the 40 frame because the magwell is wider.... cant really shim the mags either because the magazine catch is slightly shorter.

 

[mgmorden]

I've only "converted" one gun - and by that I mean I have a .357 SIG barrel for my Glock 22 but most of the time it lives with the original .40 S&W barrel in it.

I also have a (actually relatively rare) S&W Sigma SW357V originally in .357 SIG.

Both work fine, though I'm not particularly in love with .357 SIG. If I'm going to have the reduced capacity I'd rather just use .40S&W anyways.

 

[JimKirk]

When I purchased a Storm Lake 9mm conversion barrel for the M&P40 at Grabagun, the had a super offer for 9mm factory magazines. I purchased 2 of them. So I haven't tried using a 40/357 magazine with that barrel.
But now I'm curious to see if those magazines will work with the 9 next time at the range.

Kevin ... I read it somewhere on the net that the Glock 40/357 magazines would mostly feed 9mm ..... so you know me ....I gave it a try and I had no failure to feed the 9mm ....

I had purchased two Pmags Glock 17 magazines when I ordered my conversion barrel ... just so happened that Brownell had both barrel and mags on sale ....so it worked out just right ....

 

[Rockrivr1]

I've only "converted" one gun - and by that I mean I have a .357 SIG barrel for my Glock 22 but most of the time it lives with the original .40 S&W barrel in it.

I also have a (actually relatively rare) S&W Sigma SW357V originally in .357 SIG.

Both work fine, though I'm not particularly in love with .357 SIG. If I'm going to have the reduced capacity I'd rather just use .40S&W anyways.

You can get a LoneWolf 9mm conversion barrel for the G22 and make a three caliber gun. Easier/cheaper then getting a G17 just for 9mm.

 

[AustinTX]

That's why I posted the recoil comparisons.

Yes, I understand. I had others in mind when I posted.

 

[AustinTX]

Its a pretty major factor in terms of lockup wear/damage.

I don't disagree, and my previous statement is not inconsistent with this point. Peak chamber pressure is a good -- though not perfect -- proxy for how hard a given round is on a pistol within a given caliber. My other observation was that people on gun forums routinely compare peak pressures between calibers and assert on this basis alone that one caliber (e.g., .45 ACP) is easier on a pistol than another (e.g., 9mm Para.) when . . . that's not how it works at all.

 

[starling]

I don't disagree, and my previous statement is not inconsistent with this point. Peak chamber pressure is a good -- though not perfect -- proxy for how hard a given round is on a pistol within a given caliber. My other observation was that people on gun forums routinely compare peak pressures between calibers and assert on this basis alone that one caliber (e.g., .45 ACP) is easier on a pistol than another (e.g., 9mm Para.) when . . . that's not how it works at all.

I think we are on the same page. Wasnt trying to be snarky with you. If thats how I came across... I am sorry. Lots of facors involved. Even more so when you bring in different designs.

 

[AustinTX]

I think we are on the same page. Wasnt trying to be snarky with you. If thats how I came across... I am sorry. Lots of facors involved. Even more so when you bring in different designs.

I didn't take it that way, and I'm not trying to be brusque either. We're just doing some old-fashioned "discussioning."