I have a XDm in 40S&W that has enhancements for USPSA Limited competition shooting. I also have the Fire Dragon .40 to 9mm conversion barrel for it and I have had no issues with it. The conversion barrel was acquired back when ammo was hard to acquire. So I could shoot either .40 or 9mm depending on what I could find and purchase.
Before adding the extras for USPSA Limited class, it was used with the 9mm barrel in Production class. This is because this class only allows for a few enhancements. Limited class allows you to perform more enhancements to the firearm (I.E.: like adding a large mouth mag well
I have not used my converstion barrel in some time since I have a 9mm and a.40SW XDm in my collection now. My 9mm is completely stock and no enhancements have been done on it.
I am hoping and waiting for SA to release the new 5.25 XDm in .40S&W to upgrade it (I think would it just need a trigger job and thinner front post
) to be my new Limited class firearm.
Good Luck And Be Safe!!!