40 to 9 conversion recoil spring

[miles71]

I took my new m&p 40 out today and was very happy. Even happier I found some mags and barrel to do a conversion which i should receive in about a week. But now I am hearing about the green recoil springs........

I know I have asked this before, but more specifics please. Will the conversion work with just a barrel and mag switch? Are all the other parts of the pistols the same?

Great pistol, don't want it to get *****.
TD

 

[JustAnotherGunGuy]

Although I have no direct experience, the way I understand it all you need is a 9mm barrel and mags.
Congrats on getting the conversion.

 

[robkarrob]

The recoil springs are the same for 9mm and 40. Check the parts listing for each gun, and you will see the same part number listed for each gun.

Bob

 

[popo22]

I can only speak from my own experience so this is limited advice. I have a .40 FS, .40c, and .40 Shield and have purchase factory 9mm barrels for each. I am able to shoot 9mm with each one of them with no other additional replacement parts (including no 9mm magazines, I use the .40 mags). All have been 100% reliable and just as accurate as with the .40 rounds. I have shot several thousand rounds with this "set-up". Good Luck.

 

[Choot'em!]

Sooo....Does this mean If i wanted i could just buy a 40 Barrel and Swap it out on my 9mm?

 

[Choot'em!]

Sooo....Does this mean If i wanted i could just buy a 40 Barrel and Swap it out on my 9mm?

never mind did a little search

 

[DocSunShine]

The recoil springs are the same for 9mm and 40. Check the parts listing for each gun, and you will see the same part number listed for each gun.

Bob

New .40s are coming with the slightly heavier green spring (instead of blue), so this is not necessarily true anymore. Check out the thread I started on the topic.

 

[bikendan]

been running a Storm Lake conversion barrel in my 40, for about 6 months now and it works great with no need to change the spring.
just swap the barrels and mags and away you go!

 

[Gyrene6891]

I am able to shoot 9mm with each one of them with no other additional replacement parts (including no 9mm magazines, I use the .40 mags). All have been 100% reliable...

The 9MM rounds will feed with the 40 magazine but not 100% reliable 100% of the time. No problem for range duty but I would no use them for CCW.

 

[1sailor]

My .40 cal mags worked pretty well for a while but as they got looser they started letting the rounds pop out as I was loading them so I bought a couple of 9mm mags online from botach. At the time they were about $21 apeice which included shipping. I ran the factory spring for a long time but then switched to a Wolff 19lb spring and rod to help me find my brass.