Q about conversion barrels, extractors

[Dreaded Claymore]

I've been told that I can buy (for instance) an M&P chambered in .40 S&W and then just buy a conversion barrel and magazines for 9x19mm. Wouldn't the extractor have to be changed, too, since the cartridge cases are different?

[undercow16969]

Maybe a weaponsmith could have a better answer for ya. I was wondering the same thing a few months back but for a .40-.45 for HK.

[mc21]

.40 magazine work with 9mm rounds do maybe they're similar enough?

[sirgiles]

http://personaldfence.com/stormlake-40-to-9mm-conversion-for-the-mp-compact-review/

The conversion barrels (i.e. - Storm lake 40 -> 9mm ) are designed to work with the .40S&W hardware such as ejector, extractor, etc. The only thing you need are 9mm magazines.

In a standard 9mm slide w/barrel vs. a .40S&W slide w/barrel - the extractor, ejector, breach face, barrel crown, etc are all different. The caliber conversion barrel takes these differences into consideration and are generally perfectly reliable. Obviously, if you use a conversion barrel, you should fire a few hundred rounds minimum before considering it ready for self defense - but most people use caliber conversion for cheap range use and convert back for carry/duty use.

[Dreaded Claymore]

Good to know, thanks.