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Can I run .357sig ammo in a FNS40 S&W as the magazine specifies 40S&W/.357sig..357 sig is a .40 cal necked down so any and all opinions are appreciated.
 

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Can I run .357sig ammo in a FNS40 S&W as the magazine specifies 40S&W/.357sig..357 sig is a .40 cal necked down so any and all opinions are appreciated.
So I would need to purchase a FNH .357 sig barrel ?that's fits my model
 

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Since this is a conversation now, is the barrel the only thing that needs to be changed? Is the recoil spring for the 40S&W FNS fine for 357 sig? I know it might be a dumb question but I thought I would ask just in case.
 

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Since this is a conversation now, is the barrel the only thing that needs to be changed? Is the recoil spring for the 40S&W FNS fine for 357 sig? I know it might be a dumb question but I thought I would ask just in case.
Going by Glock standards only a barrel needs to be changed for a .40 S&W to safely fire a .357 Sig. It would seem reasonable to think the same would be true across multiple manufacturers. Then again, there's only one way to find out.
 

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Going by Glock standards only a barrel needs to be changed for a .40 S&W to safely fire a .357 Sig. It would seem reasonable to think the same would be true across multiple manufacturers. Then again, there's only one way to find out.
After posing that question, I actually started researching recoil springs and couldn't find one for the FNS for 357 Sig. That, and your response, leads me to believe that it is probably just a simply barrel swap.

I don't ever plan on converting one over to 357 Sig, but it is good to know info just in case.
 

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After posing that question, I actually started researching recoil springs and couldn't find one for the FNS for 357 Sig. That, and your response, leads me to believe that it is probably just a simply barrel swap.

I don't ever plan on converting one over to 357 Sig, but it is good to know info just in case.
If you consider a .40 S&W is a fairly stout li'l round wit a bit O'kick to it to begin with. Whereas the .357 Sig is fairly stout in it's own right but with a smaller lighter bullet. I would think in a world gripped by gravity and momentum these two rounds should be equal as far as the recoil spring views them. Of course, what the hell do I know anywayz...YMMV
 
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EFK Firedragon makes conversion barrels. They are taking "8wk" backorders here


I don't think they will continue to take backorders for years to come ... cal 40, while IMO better than 35, has unfortunately fallen out of fashion. To that point: if I had a FNS40 I would backorder asap while there's getting. They might kist ported or threaded on their site elsewhere.
 

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A 400 Corbon barrel for the FNX45 would be the same idea! But unfortunately not an available one.
 
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Got my FNS .40 first. Then bought another 4" slide kit as well as a 5" slide kit, both in .40 when CDNN was selling those awhile back.

The purchased .40 4" was more accurate than that original 4" barrel/slide that came on the frame so I ordered a 4" .357 SIG barrel from EFK Firedragon.

It also shoots better than the original 4" barrel that was in the new pistol.

Yes, the magazines work with either.

Thought I had some pictures, but can't find them.

One other comment. The EFK Firedragon barrel was a drop in fit (had hopes of being able to fit it myself to get a better fit to the slide. Oh well. And, the EFK Firedragon barrel was one of the prettiest, shiniest barrels on the outside I've ever seen. The bore cam also showed the inside was nicer finished than many of the factory barrels I've looked at.
 

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A 400 Corbon barrel for the FNX45 would be the same idea! But unfortunately not an available one.
You can shoot 450 SMC in the FNX 45 without any changes. * Except maybe a heavier recoil spring if you are going to shoot only 450 SMC. 450 SMC has ballistics very similar to 10mm in lighter rounds (160-200) and has factory loads in heavier hunting rounds like the 255 grain hardcast which aren't readily available in 10mm.
 

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You can shoot 450 SMC in the FNX 45 without any changes. * Except maybe a heavier recoil spring if you are going to shoot only 450 SMC. 450 SMC has ballistics very similar to 10mm in lighter rounds (160-200) and has factory loads in heavier hunting rounds like the 255 grain hardcast which aren't readily available in 10mm.
Thanks! I actually shoot 460 Rowland out of mine, when I decided I needed more (for the kids' safety) than 10mm (which I wear on my left) :D
142301
 
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Can I run .357sig ammo in a FNS40 S&W as the magazine specifies 40S&W/.357sig..357 sig is a .40 cal necked down so any and all opinions are appreciated.
Actually, you can probably shoot .357 SIG in a .40 S&W.
You can even shoot 9mm in a .40 S&W. I have done it. My Glock .40 S&W fired and even cycled the 9 mm ammo. The brass comes out chalice shaped so it not good for reloading.
Your magazine may be stamped .357 SIG/.40 S&W because the magazine will hold either ammo since the parent cartridge is the same diameter.
Now, should you shoot .357 SIG in a .40 S&W? No! Change out the barrel.
While a drop in barrel would work fine, I have heard that a barrel fitted by a good gunsmith can improve accuracy. (This is just what I have read; no personal experience.)
You can get a threaded barrel and put a compensator on it, whatever you want to do, it is your money and time.
Happy shooting and stay safe.
 
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