[cpermd]

Can I rechamber the 40 barrel and use a 10mm recoil spring?
This will be a sear host using a Coharie stamping.
The 40 kits are easier to find for me.

CP

 

[HkCHUCK]

10 mm Build

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.

 

[Glock35]

You should be good with MP5F recoil rod.
You can also ream the 40 into a 10mm. Not sure if 10mm barrels are harder to find now or not.

I'll see if I can determine the twist rates of the 40 & 10. I'm curious myself.

 

[Las_Vegas_HK]

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.

 

[cpermd]

Thanks

CP