I had a P229 that came in .357SIG and then I bought a .40 barrel for it and it worked fine. Now I have a P226 that I think came in .357SIG (been so long, I forget) and I got a .40 barrel for it, and it's always worked fine.

I'm getting out of .40 now and am wondering what kind of 9mm barrel I can just drop in and keep on shooting without any fitting or mods. Will a stock SIG P226 barrel in 9mm work? Or does it have to be a conversion from 357SIG/40 to 9mm barrel?

It has to be a .40/9 conversion barrel.

Also, do I need to change the recoil spring?

Actually, a factory 9mm barrel will work, with no other changes, as I've tried it to see, using a .40/.357 magazine. However, you should get the conversion barrel.

I have a P226 tacops that came in 40sw, I dropped in a silencerco 9mm threaded barrel and the gun runs flawlessly no issues at all.

Sorry, I read P229 in the first sentence and didn't realize you were actually asking about the P226. Deleted that post.

As many people have noted, a 9mm P226 barrel will work (usually) in a 357/40 P226 slide. The barrel hood extension of the 9 barrel is a little narrower than the slot in the breech face, but that doesn't seem to matter, at least not for occasional range use.

A 357/40 recoil spring may be too stiff for wimpy 9mm ammunition to cycle the slide properly, but perhaps not. I would get a 9mm spring to be sure.

With my P229 .357 Sig / .40 S&W, I used a Bar-Sto semi-fit conversion barrel (with just a tiny bit of fitting by Robert Burke the SigArmorer) and did NOT have to change the recoil spring. The pistol cycles perfectly and is very accurate.

The same should hold true for your P226. Just make sure it's a conversion barrel, and be prepared to expect a little work on fitting.

I think it will work fine....

why?

here is the only example I can give... back in November I bought a Sig P226 legion in 357 sig from a fellow member here.... a month ago I decided to try exactly what you asked... i took the barrel out of my standard 9mm P226 and installed it in the Legion... did not change the recoil spring, slide or even the magazine... put 9mms in the 357 mag... pistol functioned perfectly through an entire magazine... if I recall correctly... I can try it again in the next week or so if requested....


I guess some would say it might depend on ammo... I was shooting 115gr fmj from Georgia Arms.

Ok, I'll find a plain old P226 9mm barrel and give it a whirl.

Silencerco makes a threaded 9mm barrel that will work very well, should you be so inclined. My P226, originally in 357 SIG, has run hundreds of rounds, suppressed and unsuppressed, with no issues through my 2 barrels, one an OEM 9mm, the other a Silencerco threaded 9mm. A variety of ammo, different brands of factory and reloads, 115 gr, 124 gr and 147 gr. No issues. The 40/357 mags will work, but I would still suggest using 9mm mags and a 9mm recoil spring.

I have a .40 239SAS with a BarSto 9mm conversion barrel.
Needed some fitting, but I did it myself with the help of a video from BarSto. Works great and will work without changing springs or even magazines. Just swap the barrel and go shoot. I did buy a 9mm mag and spring kit, but haven't needed to use them.

Hmmm. This is tempting. Barrels in 9mm for a P226 are getting hard to find.

https://osagecountyguns.com/fi...el-9mm-bbl-mk25.html

https://www.efkfiredragon.com/...php?prod=SS2269SBCBK

Chalk me up as another that dropped in the SilencerCo 9mm barrel with no issues.

I bought a LEO surplus 226 in .357, and dropped in the barrel and swapped mags. it runs 9mm fine even with the original spring in there.

I paid right at $150 for mine about two years or so ago, and at the time it was cheaper then a SIG barrel.