Gas Block Adjustment Screw

[howdy]

What is everyone's experience making a tool to adjust the gas screw? I was thinking of starting with a square driver bit just over the size and filing down the sides until it fits, any reason that wouldn't work?

Also, I have in my notes that the screw can then be removed and swapped in a replacement M4x10mm hex socket set screw for future-proof tool compatibility. Anyone done this?

 

[paco]

I need to check but i think i have 2 or 3 sizes of this screw.

 

[howdy]

Also, I keep reading about a "crimped cover" over the gas screw, does anyone have a photo of this? Mine is just an exposed square socket screw, perhaps the gunsmith removed my crimped cover when he installed the shortened barrel and it is a disposable item?
Thanks

 

[dash]

I swear when I first wanted a FNC, I saw what you're talking about. Don't see how there could be one though since anything over that screw could interfere with the handguard clip. No evidence of one ever being placed on it.

 

[dash]

As far as messing around with it, see thread below. Pretty sure there's another that called out the thread size, but I haven't found it yet.

Questions on FNC gas adjustment screw and flash hider removal...

Question #1--- Has anyone ever figured out what size allen/hex/square drive screw is used for gas adjustment on the FNC gas block??? Mine won't eject reliably with typical .223 ammo forcing me to use the adverse setting more often than I'd like. I want to remove the "screw", clean it up, and...

uzitalk.com

 

[howdy]

I swear when I first wanted a FNC, I saw what you're talking about. Don't see how there could be one though since anything over that screw could interfere with the handguard clip. No evidence of one ever being placed on it.

Interesting, your screw looks like it may be a hex? Now I'm doubting whether mine is truly square. Perhaps this won't be as simple as filing down an oversized square into a smaller square.

 

[paco]

I'm confident that you guy know there are 2 types gasblock, with the screw on the side and the screw in the front side.
Most of you will have the FNC sporter and these have the screw on the front side. Later military types have it on the side.
also, 2 types of aliade (grenadelauncher sight) The plunger is different. The old system is the 2 legged you see on top. The later had 1 leg.

 

[paco]

The side mounted type has a M5x0.8-6g thread as i remember correct from my head. It is shorter (5mm lenght) as the front type

 

[howdy]

I'm confident that you guy know there are 2 types gasblock, with the screw on the side and the screw in the front side.
Most of you will have the FNC sporter and these have the screw on the front side. Later military types have it on the side.
also, 2 types of aliade (grenadelauncher sight) The plunger is different. The old system is the 2 legged you see on top. The later had 1 leg.

Thanks for the reply. Are you addressing the crimped cover, or just pointing out that there are 2 different gas block types in general?
Is the crimped cover only on one of the types? I don't see it in your photos.

 

[paco]

I can not translate crimped cover to my language.
There are 2 type gasblocks in the military FNC.
There are also two types grenade sights. And if you flip them up, the gasport is closed.
You need a dedicated gasplug for each type grenade sight. Both type sights fit on each type gasblock

 

[dubagel]

Interesting, your screw looks like it may be a hex? Now I'm doubting whether mine is truly square. Perhaps this won't be as simple as filing down an oversized square into a smaller square.

It appears to be a hexhead screw that has been “staked” on 4 sides so it won’t back out/unscrew.