I believe that others have posted on this. If I remember correctly one can rehamber the barrel, a 10 mm cartridge case is longer than the .40 S&W one.
I don't think anyone has commented on the difference in twist rates between the two barrels but I know that their is a difference. I don't know if it has any impact on accuracy that would matter. Seems to me some have commented on the recoil spring for a 10mm. Was it that Hk recommended using the 53 recoil spring? Not sure of that one without doing some checking.
IGF can ream the 40 S&W chamber to a 10mm. There are several people who have had them do it.
A MP5 10 recoil spring in the same as a HK53 one. The MP5 40 uses the MP5 F recoil spring.
You would also need to change your locking piece.
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