How many pistols can switch from .40 to 9mm?

Glock, SIG, M&P. The top three I can think of off the bat.

Springfield XD

DUH! What was I thinking. Thanks CZ

You're welcome!

The above conversions could only be done with 9mm conversion barrels in conjunction with .40 slides, as well as 9mm magazines. The makers of these barrels, AFAIK, only recommend them for range practice, not actual carry/self defense. Otherwise - using the Glock as an example - you would have to swap a 9mm slide, barrel and ejector. (The .40 is straight, the 9mm is bent inwards.) Slides and barrels separately could rival the cost of a new gun, plus the hassle - and possible inadvertent mismatch - of all that parts swapping.

Tangfoglio's Witness series of pistols have been around for a while and have slide sets that are interchangeable for everything from 9MM to .45ACP and 10MM, with the .40 cal thrown in to boot. Mine changes slide sets and magazines and works flawlessly. For a SHTF scenario pistol, a good Witness compact with multiple slide sets is the way to go. They eat anything they're fed, and combined with a second .22 rifle/pistol combination (separate guns in .22 cal), offer a full compliment of hunting and survival options.

The Witness series is often overlooked because of EAA's customer service, but the guns are solid, and do what they're advertised to do. Like a lot of guns, a good gunsmith can fix most problems with steel guns, but not always with polymer ones... so there's also something to be said about finding a gunsmith with a machine shop. "Armorers" are sometimes nothing more than "parts changers", but a true gunsmith can manufacture a part to make guns work... often better than the original condition.

Take a look at the Witness series of guns, and you'll find a jewel. My compact (especially in 10MM) is awesome...

WT

The Berretta/Taurus 96 can also be converted for 9mm use.

I stuck a 9mm barrel & mag in a SIG P239 .40 and it worked fine. SIG said it doesn't work with all pistols. Kind of a hit or miss thing.

The Lone Haranguer said:

The above conversions could only be done with 9mm conversion barrels in conjunction with .40 slides, as well as 9mm magazines. The makers of these barrels, AFAIK, only recommend them for range practice, not actual carry/self defense. Otherwise - using the Glock as an example - you would have to swap a 9mm slide, barrel and ejector. (The .40 is straight, the 9mm is bent inwards.) Slides and barrels separately could rival the cost of a new gun, plus the hassle - and possible inadvertent mismatch - of all that parts swapping.

Click to expand...

Hmm...I was under the impression that for Glocks you just swap to a conversion barrel and mags....did I read something wrong? Lonewolf and storm lake never mentioned swapping slides or extractors

Hmm...I was under the impression that for Glocks you just swap barrel and mags....did I read something wrong? Lonewolf and storm lake never mentioned swapping slides or extractors

Click to expand...

With Glocks, the barrel swap will work, but probably won't be as accurate as a proper barrel. The outside diameter of most .40 barrels is larger than the 9mm barrel, so there is a little slop when the standard 9mm barrel is installed. A little. (I wouldn't be surprised if there was some accelerated wear on the barrel locking lugs on some guns, too, if the swapped barrel was shot a lot.) There are a number of videos on YouTube showing it being done with a Glock. I think I'd rather have a conversion barrel, myself.

With the older Witnesses (at least with the small-frame versions), the barrels for the 9mm and .40 were the same diameter, and the mags woulds work either way, too.

Just about any .40 can be made to shoot 9mm with a conversion barrel. Sometimes you need to change to 9mm mags, sometimes you don't, depending on the traits of the specific gun maker's mags. (A CZ .40 mag won't retain a 9mm round, but the older Witness .40s mags would retain the 9mm round.) You'll have to experiment.

I had a very nice SIG 2022 with a .357 SIG (.40 barrel dimensions) barrel and a 9mm Bar-Sto barrel. Shot beautifully if you used 9mm
mags, but wouldn't lock back on the last round -- and SIG said both models used the same slide stop.

Properly designed conversion barrels are made to work with the existing extractors and headspace is not an issue. None of the conversion barrels I've seen required extractor changes -- but they were all 40/9mm conversions. My SIG convesion barrel didn't require changes.


.

I have 9mm conversions for my Glocks (22,27, & 32) and Beretta's and have not had any problem with extraction during firing, although if I slowly pull the slide back the rounds will fall out rather than eject out.

I was unaware of Sig converting.... I looked and looked...dang -- oh well. I got a Glock 22 so i'm happy.

With Glocks, the barrel swap will work, but probably won't be as accurate as a proper barrel. The outside diameter of most .40 barrels is larger than the 9mm barrel, so there is a little slop when the standard 9mm barrel is installed.

Click to expand...

Yes, using factory 9mm barrels in 40S&W slides will operate the slide but I really recommend the conversion barrel that has the same 40S&W outside barrel dimensions for accuracy.

The entire G17 slide/barrel swap will work in G22 frame and vise versa. I believe the recoil spring rate on Gen2/Gen3 are still same.

My experience with Lone Wolf conversion barrels has been that they do not require extractor replacement as the extractor makes enough grip on the 9mm case rim. G22/G23 require the use of G17/G19 magazines as the magazine follower feed angle is different, but my G27 magazines work fine with 9mm.

Yup, conversion barrels give you the best of both worlds in 9mm and 40S&W.