Converting Browning .40 S&W HP to 9mm?

[velocette]

I have a BHP Mk III .40 S&W which I would like to switch back & forth to 9mm. Much cheaper ammo, less recoil, cheaper ammo, less muzzle blast less recoil & did I mention cheaper ammo.
I've heard that all is needed is a 3 lug 9mm barrel and the appropriate 9mm magazine. Is this true? Or what else is needed?

TIA
Roger

 

[Scorch]

New barrel, appropriately fitted, especially at the lugs and the barrel bushing.
Appropriate magazine.
Different recoil spring.

 

[Lazy D]

Not that easy

You can just put in a different barrel. The bolt face is too large on the 40. You will have a problem w/ extraction and ejection. The 40 extractor will not grab the rim of the 9mm. This allows the case to fall off the bolt face before it can be ejected my the ejector. You might see if you can find an old slide off of a 9mm and just switch the whole uppers. Good luck.