# Converting 40 cal to 9 mm



## chevy bob (Aug 25, 2018)

Hello all, 
I'm a newbie on this forum so this is my first post. I have a Sig 320 in 40 cal . and would like to know what parts that I would have to change to make this conversion to 9mm.According to some info I read online, the only things that would have to change would be the barrel and possibly the recoil spring.I was just wondering if anyone here has ever done this conversion before. I know there is a lot of knowledge on this forum so any help would really be appreciated . THanks in advance


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## denner12 (Oct 14, 2017)

Unless someone makes a 9mm converison barrel for the P320, I would think you would need the whole Sig conversion kit which would include a 9mm slide and barrell. You would need 9mm magazines as well. If it were me, I'd call Sig to confirm. And yea, I don't like using factory rated recoil springs in 9mm for 40 and vis-a versa.


The fact is: 9mm standard pressure ammo has noticiably less recoil than standard .40cal ammo. 9mm +p and +p+ just maybe a little less recoil.


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## pblanc (Mar 3, 2015)

Yes, I agree with denner12. You need a conversion kit which will include a new slide, barrel, recoil spring assembly and one magazine. SIG calls them "caliber X-change" kits.


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## chevy bob (Aug 25, 2018)

tThabks


pblanc said:


> Yes, I agree with denner12. You need a conversion kit which will include a new slide, barrel, recoil spring assembly and one magazine. SIG calls them "caliber X-change" kits.


Thanks for the input guys, but I am trying to avoid buying the conversion kit due to the high cost. They want as much for a conversion kit as it would cost me to buy a brand new 9mm pistol. I think that I read somewhere that Glock does make a conversion barrel for one of their 40 cal. pistols to 9mm. Just thought Sig had something too .


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## pblanc (Mar 3, 2015)

Well lo and behold, this seems to be hot of the presses. Bar-Sto is now making 9 mm conversion barrels for the SIG P320:

Bar-Sto Precision Machine

Bar-Sto has long made conversion barrels for the classic P-series SIGs and they are generally very well regarded. You are still going to need 9 mm magazines and may have to swap your recoil spring assembly.


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## chevy bob (Aug 25, 2018)

TThanks pblanc. I don't think there is a cheap way to do this


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