FNX .357 Sig and .400 Corbon Questions

Cosmodragoon · December 4, 2016, 11:59 PM

Yes, I know these cartridges are more expensive, relatively obsolete, not as good as 10mm, etc. I don't care. I'm just doing a little Christmas thinking and wanted to tap my favorite knowledge base.

I'm wondering if anyone has tried the conversion barrels for .357 Sig or .400 Corbon in the FNX-40 and FNX-45, respectively. I had heard that large double-stack magazines can pose feeding problems, especially for the .400 Corbon, and it doesn't get much bigger than the FNX. So do you have any firsthand experience with these? Do you know someone who does? Do you just use them at the range or do you trust them in your carry gun? I'd love to hear your thoughts on these.

GarrettJ · December 6, 2016, 10:05 PM

I bought a .400 Corbon barrel for a 1911 in the mid '90s. I found the problem with the round was the neck was too short. It didn't provide enough neck tension to keep the bullet in place. About half of the bullets would get pushed back in the case when chambering a round.

This was true for both factory ammo and reloads. I ended up selling it off a few years later.

Cosmodragoon · December 7, 2016, 04:18 PM

I posted this over on the FN Forum too. I know this is a rarer item but I figured more people would have tried them.

I called EFK and spoke with Kim. Not surprisingly, she had a lot of confidence in the product and hadn't heard of any problems. She seemed honest though, and had a good sense of humor. She said that the .357 Sig version has been popular and she hasn't seen any returns or complaints. Unfortunately, she hadn't seen or heard much at all with respect to the .400 Corbon barrel. She told me that in any case, they'd stand by their product if there was a problem.

I'll probably pick up the .357 Sig version but I've got to think about the .400 Corbon. The idea is compelling: achieving 10mm power levels with moderate recoil in a high-capacity DA/SA gun. Of course, it's only good as far as it actually works. I'm hoping we'll find some more folks who've tried it.

dontcatchmany · December 7, 2016, 06:26 PM

I have the FNX 40 and the FNS 40 and the FNX 45.

I have a 357 Sig barrel that I can use in either of the 40s.

Never a problem.

I know nothing of the 400 corbon.

MarkCO · December 7, 2016, 06:45 PM

I had issues with the 400CorBon in a 1911 and a Glock. Got a .40 Super and kept that.

Cosmodragoon · December 8, 2016, 01:20 AM

Quote:

I had issues with the 400CorBon in a 1911 and a Glock. Got a .40 Super and kept that.

Is the .40 Super inherently more stable than .400 Corbon in the .45acp magazines? I don't know much about it but from a quick look, .40 Super is the same concept as .400 Corbon but operates at a significantly higher energy level. Is it rough on the gun? How is the recoil? I saw spring upgrades and porting mentioned in that quick search.

Dag... now you've got me thinking about this one too!

MarkCO · December 8, 2016, 09:09 AM

The .40 Super is better feeding from the magazines than .400 CorBon.

It is a thumper and it is rough on guns. Mine is in a custom 1911 with all of the strongest and close tolerance parts I could get. It has a spherical bushing from Briley which is almost a necessity. It is a 6" barrel. Have a 5" .45 barrel for it as well.

I "borrowed" .40 Super Dies from Dillon and loaded 2000 rounds after load development. I have about 1000 left.

I also have about 50 factory rounds from Triton, but it is not made anymore.

Yes, it needs a very strong spring, but too strong and you mess up timing and damage rounds as the slide goes into battery too fast.

TRX · December 9, 2016, 05:23 PM

I have bullets, fresh powder, new primer, new brass, new die set, new .40 barrel, loading data... still waiting for the freakin' .40 Super reamer to show up.

Mine's a 6" barrel too, with a 6" slide. Or it will be, when the reamer gets here.

December 4, 2016, 11:59 PM	#1
Cosmodragoon Senior Member Join Date: March 18, 2013 Location: Northeastern US Posts: 1,869	FNX .357 Sig and .400 Corbon Questions Yes, I know these cartridges are more expensive, relatively obsolete, not as good as 10mm, etc. I don't care. I'm just doing a little Christmas thinking and wanted to tap my favorite knowledge base. I'm wondering if anyone has tried the conversion barrels for .357 Sig or .400 Corbon in the FNX-40 and FNX-45, respectively. I had heard that large double-stack magazines can pose feeding problems, especially for the .400 Corbon, and it doesn't get much bigger than the FNX. So do you have any firsthand experience with these? Do you know someone who does? Do you just use them at the range or do you trust them in your carry gun? I'd love to hear your thoughts on these.

December 7, 2016, 06:45 PM	#5
MarkCO Senior Member Join Date: October 21, 1998 Location: Colorado, USA Posts: 4,307	I had issues with the 400CorBon in a 1911 and a Glock. Got a .40 Super and kept that. __________________ Good Shooting, MarkCO www.CarbonArms.us

December 8, 2016, 09:09 AM	#7
MarkCO Senior Member Join Date: October 21, 1998 Location: Colorado, USA Posts: 4,307	The .40 Super is better feeding from the magazines than .400 CorBon. It is a thumper and it is rough on guns. Mine is in a custom 1911 with all of the strongest and close tolerance parts I could get. It has a spherical bushing from Briley which is almost a necessity. It is a 6" barrel. Have a 5" .45 barrel for it as well. I "borrowed" .40 Super Dies from Dillon and loaded 2000 rounds after load development. I have about 1000 left. I also have about 50 factory rounds from Triton, but it is not made anymore. Yes, it needs a very strong spring, but too strong and you mess up timing and damage rounds as the slide goes into battery too fast. __________________ Good Shooting, MarkCO www.CarbonArms.us

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December 6, 2016, 10:05 PM	#2
GarrettJ Member Join Date: April 13, 2008 Posts: 94	I bought a .400 Corbon barrel for a 1911 in the mid '90s. I found the problem with the round was the neck was too short. It didn't provide enough neck tension to keep the bullet in place. About half of the bullets would get pushed back in the case when chambering a round. This was true for both factory ammo and reloads. I ended up selling it off a few years later.

December 7, 2016, 04:18 PM	#3
Cosmodragoon Senior Member Join Date: March 18, 2013 Location: Northeastern US Posts: 1,869	I posted this over on the FN Forum too. I know this is a rarer item but I figured more people would have tried them. I called EFK and spoke with Kim. Not surprisingly, she had a lot of confidence in the product and hadn't heard of any problems. She seemed honest though, and had a good sense of humor. She said that the .357 Sig version has been popular and she hasn't seen any returns or complaints. Unfortunately, she hadn't seen or heard much at all with respect to the .400 Corbon barrel. She told me that in any case, they'd stand by their product if there was a problem. I'll probably pick up the .357 Sig version but I've got to think about the .400 Corbon. The idea is compelling: achieving 10mm power levels with moderate recoil in a high-capacity DA/SA gun. Of course, it's only good as far as it actually works. I'm hoping we'll find some more folks who've tried it.

December 7, 2016, 06:26 PM	#4
dontcatchmany Senior Member Join Date: July 19, 2010 Posts: 460	I have the FNX 40 and the FNS 40 and the FNX 45. I have a 357 Sig barrel that I can use in either of the 40s. Never a problem. I know nothing of the 400 corbon.

December 9, 2016, 05:23 PM	#8
TRX Senior Member Join Date: September 24, 2008 Location: central Arkansas Posts: 400	I have bullets, fresh powder, new primer, new brass, new die set, new .40 barrel, loading data... still waiting for the freakin' .40 Super reamer to show up. Mine's a 6" barrel too, with a 6" slide. Or it will be, when the reamer gets here.