Anyone shorten your FNC Barrel?

[RM308]

I am getting ready to send my FNC, sear and pack out for installation.

And like the title says, I'm thinking about shortening the barrel and want some input on what has been done and what works with the existing gas system when shortening a standard barrel. Oh yeah, I want it to be threaded 1/2X28 for an easy Suppressor installation later.

Thanks, guys.
RM308

 

[hoverflt]

If you want to shorten the barrel. I suggest getting a new 1:7 twist fnc barrel from Green Mountain.

 

[copper]

You can shorten the barrel to 14.5" and it should still function fine (mine did). At most, you may have to adjust the screw on the front of the gas block or turn the gas tube to the adverse setting. The problem is, it's not easy to pull the barrel from the receiver to put it in a lathe like an ar15 barrel. You can just use a hacksaw to cut the barrel, true it up with a file, and rethread it by hand using a thread alignment tool and a 1/2x28 die. The FNC barrel is just over 1/2 inch in diameter at the 14.5" length, so it's very easy to do, but it may not be precise enough to use with a sound suppressor. It probably would be close enough if you use a .308 suppressor on your FNC, which will sound almost exactly like using a .223 suppressor, but it will weigh a bit more.

 

[RM308]

If you want to shorten the barrel. I suggest getting a new 1:7 twist fnc barrel from Green Mountain.

Good idea.

You can shorten the barrel to 14.5" and it should still function fine (mine did). At most, you may have to adjust the screw on the front of the gas block or turn the gas tube to the adverse setting. The problem is, it's not easy to pull the barrel from the receiver to put it in a lathe like an ar15 barrel. You can just use a hacksaw to cut the barrel, true it up with a file, and rethread it by hand using a thread alignment tool and a 1/2x28 die. The FNC barrel is just over 1/2 inch in diameter at the 14.5" length, so it's very easy to do, but it may not be precise enough to use with a sound suppressor. It probably would be close enough if you use a .308 suppressor on your FNC, which will sound almost exactly like using a .223 suppressor, but it will weigh a bit more.

I am not comfortable with this as a do it yourself project (at least for me). So I am asking for a quote to do this when I have the sear installed.

Thanks
RM308

 

[jimdet]

Shorten barrel

I'm sure you know that as long as the gun is converted to FA you have no problem shortening the barrel. I have all my full auto"s shortened and have no problems with them. Of course if you ever decide for any reason to convert your gun back to semi you will need to re barrel again. Who is installing your sear? If it's TBA Suppressors you can have Todd do it when he does the installation. He also makes a real nice threaded flash hider that you can quickly attach his suppressor with.

 

[quasi]

Go No Shorter than this...

Yes, 1/2x28 works well on the FNC.

 

[RM308]

I'm sure you know that as long as the gun is converted to FA you have no problem shortening the barrel. I have all my full auto"s shortened and have no problems with them. Of course if you ever decide for any reason to convert your gun back to semi you will need to re barrel again. Who is installing your sear? If it's TBA Suppressors you can have Todd do it when he does the installation. He also makes a real nice threaded flash hider that you can quickly attach his suppressor with.

Knew that about shortening, Thanks.

Go No Shorter than this...

Yes, 1/2x28 works well on the FNC.

That's what I was thinking. Thanks

 

[okpud]

I end up doing 5 - 6 a year for customers. I also end up fixing 1 - 3 a year that were done improperly by other gunsmiths... We've done something around 25 re-barreling on FNCs, and ~2/3 of our customers opt to go SBR w/ 1/2x28 RH threads. You do have to open up the gas port on the SBR for proper full auto function. The gas screw in the front is 1) not present on all FNC gas blocks and 2) not antiquate to provide enough adjustment for most SBRs. It is there for fine tuning, not to cover a wide range of barrel lengths. Cutting the barrel form 17.7" to ~14.3" decreases the dwell time too much for most ammo w/o the gas port adjustments. Running your FNC in the "adverse" gas setting will reduce this, but you shouldn't have to run it that way for normal shooting.

FNC barrels are not like AR-15 barrels. They are not thread clocked, do not "automatically head space", and the gas block are easy to damage w/o the right removal tools (you can't just beat them off w. a mallet and punch). This is the reason the when we worked w/ Green Mountain to have the new barrels made from our sample barrel, we jointly decided no to have the gas ports pre-drilled. I.E. you can't pre-drill them and have the headspacing correct. You also need a proper receive block and vise to remove the original barrel w/o torquing the receiver. Whoever you choose to do the barrel work, make sure they have a decent track record re-barreling FNCs.

 

[gman552]

I end up doing 5 - 6 a year for customers...

Do you have a website and price list? Does the customer need to supply the GM barrel if they decide to replace it? Turnaround time?

 

[okpud]

Do you have a website and price list? Does the customer need to supply the GM barrel if they decide to replace it? Turnaround time?

Hi Gman, since this is not a "services for sale" forum, I'll point you to the sticky I got permission from the mods to post ->

http://www.uzitalk.com/forums/showthread.php?54671-FNC-Barrel-Replacement-Overview&p=642738#post642738

It has our contact email address in it, along with the cost of a basic barrel install. Because GM has changed the barrel cost a few time, we require customers to supply their own barrel. I'm happy to answer any direct queries via our contact email.