I've done quite a bit of searching but cannot find a definitive answer..

Can I put a classic 9mm folded slide/barrel/recoil spring on a 40 lower? With just a upper swap?

Every conversion search I do points me in the direction of a conversion barrel, or caliber exchange kit.

The police surplus 40's seem to be readily available, and I've seen a couple 9mm folded slides being gunbrokered off.

They look like they should work fine. But again... cannot get a real definitive answer.

I tried it a while back and it worked fine.

By the time you buy a .40 trade in and a 9mm slide assembly you could probably just buy a 9mm P226 for the same money.

It usually works to do that; I gave a friend such a combination. Most older frames used with carbon steel 9mm slides were the same as the frames used with 40 S&W slides. The thing to worry about is whether individual tolerances might cause a problem.

You may find that the 40mm slide catch-ejector in the frame won't work properly with the 9mm round. You may need to replace it with the 9mm version.

Already have the folded slide assembly, so that cost was absorbed years ago.

Do I need to change to a 9mm ejector? Looks like they are only a coupe bucks anyway

quote:

Originally posted by fullmann:
Do I need to change to a 9mm ejector? Looks like they are only a coupe bucks anyway

No.

Many people have made the conversion by different means and I have never read that anyone discovered it was necessary.

(The P226 ejector is not part of the slide catch lever—unlike the P220.)