M&P compact 40/357 to 9mm conversion

[B96brig4CC]

Took the plunge and bought a storm lake barrel to convert my M&P 40c to 9mm. Bought 2 factory 9mm mags w/ finger extensions from cheaper than dirt. My question now will be if I will need a new spring. I guess I will just have to run a couple once I get it and see if the 40 spring is to stiff for 9mm or not. Also bought me a TLR-3 light for it.

Has anyone tried this conversion and what did you find with the stock spring?

 

[grwd]

40 spring is the same as 9mm

 

[B96brig4CC]

40 spring is the same as 9mm

Coming from a man who should now. Thanks for the info. Now the wait for it to arrive so I can use it.

 

[DaveTec]

I've been told that the MP40c will accept the 15rd magazine from the the full sized MP40. Is that true, and if so, it would stand to reason that the same would be true for the 9mm. Hmm......

I've been mulling over the purchase of a MP40c to go with my full sized MP40. This post may have just cemented that decision. Thanks!

 

[blutch]

DaveTec. This is true.

B