If you are talking about conversions for HK, to my knowledge that is not a straight drop in between .40 and 9mm. You would need to have the respective slide (full size or compact) as well. For .40 to .357 swap, that would be a straight drop in of the barrel, that is all that is needed.
For sure not a straight drop in. The OD of the 40 barrel is larger than the 9mm. Factory 9mm barrel will not work in the 40 slide. Tons of companies make a larger OD 9mm barrel to drop into the 40 slide for Sig and Glock (I have a Bar-Sto for one of my Sigs) but have not found one for any HKs. I want this so I can put my can on my USPc or USPf. Thought about a 40 can but the 9mm is quieter and a barrel would be chaper than a new can or a USP 9mm SD.
I know I can take a factory 357 barrel and drop it right into a compact or full sized 40 and vice versa and use the same mags. You can not drop the factory 9mm barrel into either of the 40 or 357 slides and expect it to work. Like I was saying I have a 40 to 9mm conversion for a P229 40 and it works perfectly with a 9mm recoil spring. My uncle has the same for a Glock 23. I need the same for a USPc. I have seen that EFK fire Dragon seems to have made on but has non.
I know the extractor may be slightly different, the breach face is larger, the recoil spring is heavier on the 40 and 357 vs. 9mm, etc. etc. I have personally used the conversions in two different mfgs firearms and they work perfectly. I realize it may work perfectly, have to be tweaked, or not work at all but is anyone aware of a manufaturer currently making such a product? I appreciate all of the advice and tech info but basically all I am getting is why it will not work and not who might make it.
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