Letter: .40S&W Conversion for 9mm


“Beretta 9mm Model 92/Centurion Owners – .40 S&W Kits Now on the Market”

How long ago was this posted? Do you know if they still have the kits available? If so, can you direct me to it on the website?

Thanks – HKL

Hugh Replies: I would be careful about any conversion to bring a 9mm to .40S&W.

I know the intent was to have the .40S&W available on 9mm frames, but the cartridge has considerably more energy than the 9mm. I had a .41AE conversion for a Browning HP that destroyed the HP. The locking lugs were rolled back to the point that accuracy was affected. The primer face of the case is also larger on the .40 than on the 9mm. Some conversion designs will accommodate this and others require the replacement of the slide.

The 92 has had problems with the slide/frame cracking on higher power 9mm rounds (the infamous sub machine gun rounds), and the .40S&W has quite a bit more energy than those rounds.

When the .40 first appeared, most gun manufacturers rushed deployment of a .40 based on their 9mm frames, and you will notice most of those are now off the market or have been heavily modified. To my knowledge, there are two viable firearms that can be converted back and forth safely and that are reliable in either configuration. The Browning HP in .40S&W has an extra locking lug added over the 9mm version. Bar-Sto makes a 9mm barrel for it which will make it into a 9mm weapon that can eat any 9mm round with ease (including the sub machine gun round and +P+ Corbon rounds). IMI’s Jericho also offers a conversion and I have heard good things about that firearm. I’d stay away from any firearm designed for 9mm and simply converted to .40S&W. You are much better off with a purpose designed .40 which can be converted to 9mm. However, unless you are specifically wishing to have a firearm that can be converted, I would stick with one caliber and a pistol designed for that caliber.