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View Full Version : Is the gas port drilled after hard chroming?


Max Collins
02-01-10, 14:02
Simple question:

Is the gas port in an AR barrel drilled before or after it is lined with hard chrome?
Max Collins
02-04-10, 12:52
Anyone?
markm
02-04-10, 20:45
Of course. The gas port has to be drilled after the barrel extension is installed. The port is indexed off of the TDC of the barrel once the extension is in place.

I could be wrong though!
ZeroDistortionNow
02-05-10, 07:46
Of course. The gas port has to be drilled after the barrel extension is installed. The port is indexed off of the TDC of the barrel once the extension is in place.

I could be wrong though!

That would make the most sense....

I see there are barrels that are being sold without barrel extensions though, so that makes me wonder about the process and what comes first (the extension or the port hole
markm
02-05-10, 14:08
That would make the most sense....

I see there are barrels that are being sold without barrel extensions though, so that makes me wonder about the process and what comes first (the extension or the port hole

Those must certainly have no port drilled.
rob_s
02-05-10, 14:14
Of course. The gas port has to be drilled after the barrel extension is installed. The port is indexed off of the TDC of the barrel once the extension is in place.

I could be wrong though!

Why couldn't the extension be indexed off the gas port? and why would the extension need to be in place before crome-lining?
C-Fish
02-05-10, 17:06
Why couldn't the extension be indexed off the gas port? and why would the extension need to be in place before crome-lining?

As I understand it...Barrel extensions are produced with no regard for timing.


You must install the extension, then drill the port "to" the extension.
markm
02-05-10, 22:29
As I understand it...Barrel extensions are produced with no regard for timing.

You must install the extension, then drill the port "to" the extension.

That's the only logical way it could work as far as I can figure. :confused:

Doing it the opposite way would be an ass ache and more costly.
Max Collins
02-09-10, 21:35
Soooooo.....

Is the barrel chromed lined BEFORE or AFTER the gas port is drilled?
markm
02-10-10, 19:07
Soooooo.....

Is the barrel chromed lined BEFORE or AFTER the gas port is drilled?


I hope someone chimes in... I would bet every gun I own that the port is drilled after the chrome lining. But I have not actually witnessed this.

Bump anyway.;)
5pins
02-10-10, 20:16
I don’t know if the gas port is normally drilled before chroming or not but, I did have a barrel where the manufacture did not drill the gas port. I sent it back to them so it could be drilled. So I know that it can be done. I just don’t if it’s normally done that way or not.
markm
02-10-10, 21:20
I don’t know if the gas port is normally drilled before chroming or not but, I did have a barrel where the manufacture did not drill the gas port. I sent it back to them so it could be drilled. So I know that it can be done. I just don’t if it’s normally done that way or not.

Yep. Drilling it after the fact is the easier way to do it in my logic process.

But what the hell do I know... and what's the diff any damned way?
Col_Crocs
02-11-10, 04:19
I agree. It seems like the more logical way to go then park after drilling so the hole gets parked too.
A benefit I could see from drilling prior to chroming is if they chromed the gas port as well but with the build up/thickness issues resulting from chroming, I doubt theyd ever do it. Unless of course they oversize it a bit so it ends up measuring exactly as intended after chroming if that's even possible...