Gas Port hole in AR barrel.

[MGYSGT]

Bought a 6.5 Creed Barrel for an AR 10 I am building. The hole for the gas port looks pretty small compared to other AR's in the M4 mode that I currently own (for the time being). How large should the hole be?

 

[swehrman]

I doubt that there is a standard for AR10 barrel gas port dimensions. There is a larger volume of gas in a 6.5 creedmoor when compared to a .223, and most AR10's in my experience are already over gassed. I wouldn't try and compare it with the port in your M4.

-- Scott

 

[243winxb]

http://www.tacticalmachining.com/learn/ar-style-rifles/ar-15-gas-port-sizes.html

Use an adjustable gas block, start there. Not only size , but location of port counts.

The powders burn rate also has an effect. Some Ar15 223 can't function with IMR 4198 and lite bullets.

How large should the hole be?

.

I have no idea.

 

[RWO]

The dwell time ( bullet passage from port to muzzle) also affects port size.

RWO

 

[rgc54]

Powder burn rate and bullet weight affect the gas pressure curve. I use adjustable gas blocks on all of my ar builds so as not to beat the weapon to death.

 

[akajun]

Last 6.5 ar10 barrel I cut the gas port was pretty small, I want to say in the .075-.085 range. I always drill mine small then go to the range with a set of number size hand reamers and start going up in size till it locks the bolt back.

 

[PatMiles]

What akajun said.
Adjustable gas block with port wide open to start with. If you just guess and drill too big, you can beat the gun up.

 

[SG4247]

I drill my 6.5x47 and 6.5 Creed AR-10 barrels to .080".

No issues when used with an adjustable gas control.

 

[MGYSGT]

Thanks for the replies, I already have an adjustable gas block. Just thought the hole was too small. We shall see.