What do I need to do this conversion? Obviously a barrel and mags, but what recoil spring is needed?

And what is a good source for the required parts?

Heck,I’d love to have a .22lr conversion as well.

Thank you!

To do it right you will need slide with 9mm barrel and recoil spring as well as some 9mm magazines...

It might work okay for practice with just the barrel and recoil spring and magazines... but I would not trust it for defense of one's or others life.

Thank you!

quote:

To do it right you will need slide with 9mm barrel and recoil spring as well as some 9mm magazines...

Or, just get the conversion barrel from Bar-Sto.

quote:

Originally posted by 12131:
Or, just get the conversion barrel from Bar-Sto.

This!!!!

I never thought of bar-sto. Great idea.

9mm rounds will not work in a 40 cal double stack magazine....

Also, what is the difference between a Bar-Sto 9mm barrel and a Sig Factory one?

Bar-Sto makes a 9MM CONVERSION BARREL.I have one in a 226st that functions perfectly. Some minor fitting is usual.My 226st came 357sig but it functions and feels great.I now keep the 9mm barrel in most of the tine.I did not change springs and have never had a issue.

quote:

Originally posted by Blume9mm:
9mm rounds will not work in a 40 cal double stack magazine....

Also, what is the difference between a Bar-Sto 9mm barrel and a Sig Factory one?

The Barsto conversion barrel has a different locking lug so it can engage the .40 locking block. It's also the proper external diameter to engage the barrel channel in the front of a .40 slide. IIRC Barsto also makes same-caliber replacement barrels for Sigs, but for what the OP is trying to do he'll want the conversion barrel.

The one issue I've have with Barsto barrels is that their throats are very short, and as such certain bullet profiles can cause the bullets to get jammed in the lands. If all you ever do is shoot factory ammo, it probably won't be an issue (unless you venture into really boutique stuff), but as a reloader it's kind of a PITA. Rounds that would pass the plunk test on every other 9mm I own wouldn't on that Barsto barrel, and I couldn't use some of my favorite bullets without having to seat them deeper than I was comfortable with.

quote:

Originally posted by Blume9mm:
9mm rounds will not work in a 40 cal double stack magazine....

Also, what is the difference between a Bar-Sto 9mm barrel and a Sig Factory one?

9mm is actually just fine in a 40/357 P226 magazine. This is because the P226 didn’t really get a magazine optimized for 40/357 like the P229 did. You may have issues with some older 40/357 P226 magazines being a little too wide at the opening (ban era mags and such), but in general, 9mm works. You just have to count the rounds manually.

If we’re talking a 40/357 slide, then the 9mm Bar-Sto conversion will actually have the same outer dimensions as the factory 40/357 barrel. So it will fit more closely in 40/357 slide than a factory 9mm barrel would.