Welding oversized gas port?

[sidewaysil80]

I have a brand new 6920 barrel that I sent off to have cut down and the port opened up to .070”. Unfortunately the gas port was overly enlarged due to an internal communication issue at the shop. I want to reuse the front sight post/gas block so simply installing an adjustable gas block is out of the question.

The shop is incredibly helpful and offered to either weld the port and redrill or replace with a new Colt barrel (in another email). I don’t want them to have to source a new barrel if the weld method is equally or even stronger than a factory gas port. But I’m unsure how durable it would be and if would erode quicker or be a weak point. Has anyone ever heard of this technique or is familiar with welds on a gas port? Here is there explanation below...

For "repair", the hole can be laser welded and re-cut. The weld does NOT get into bore line so no worries of burrs. If for any reason we look at it and decide that isn't a suitable fix, we'll replace the barrel with a new one. We've closed holes with the welding/re-cut in the past for various reasons and it has always worked fine. The welding is via a microscopic laser and it leaves very little weld on the barrel surface. But that all gets cleaned up. Barrel shouldn't need re-parking but if it does we use the same parkerizing solution Colt and other .gov MFGs use.

[Inkslinger]

Try this. This is product developed by member Clint.
http://www.blackrivertactical.com/co...tune-gas-port/

[sidewaysil80]

Try this. This is product developed by member Clint.
http://www.blackrivertactical.com/co...tune-gas-port/

Thanks, I’ll look into that more when I get home. I wonder how it would compare to welding and redrilling in terms of longevity and erosion.

[Inkslinger]

Thanks, I’ll look into that more when I get home. I wonder how it would compare to welding and redrilling in terms of longevity and erosion.

Erosion of the port is more of an issue in the bore, so I don’t think it would be an issue.
https://www.m4carbine.net/showthread...-AR-15-Barrels

[HeruMew]

I dunno...

You're talking nitrocarburized steel. Any metal they add to it will wear faster. Significantly faster. I just can't imagine how they would get it really precise and pentrated weld without risking metal getting into the barrel itself or only lightly tiging it and, again, risk of lack of penetration and wear resistance.

I am no shop worker or metallurgist. So, Your Mileage Will Certainly Vary.

I'd be flustered and ask them to source a new one. Just my opine though.

[Clint]

I would never recommend welding a barrel.

We're talking about a stress relieved alloy steel pressure vessel, not a mild steel trailer hitch.

If the shop is willing to replace the barrel, that is the best option.

Otherwise, a port can easily be installed into the existing FSB.

[HelloLarry]

I would not sweat it too much. Tap it, insert a set screw, drill that and grind off any protrusion. The set screw should not go all the way through.

All the erosion is going to happen in the barrel at the port, just like it was going to happen there in the first place.

Barrels are a consumable. Shoot it until it croaks.

[scottryan]

I have a brand new 6920 barrel that I sent off to have cut down and the port opened up to .070”. Unfortunately the gas port was overly enlarged due to an internal communication issue at the shop. I want to reuse the front sight post/gas block so simply installing an adjustable gas block is out of the question.

The shop is incredibly helpful and offered to either weld the port and redrill or replace with a new Colt barrel (in another email). I don’t want them to have to source a new barrel if the weld method is equally or even stronger than a factory gas port. But I’m unsure how durable it would be and if would erode quicker or be a weak point. Has anyone ever heard of this technique or is familiar with welds on a gas port? Here is there explanation below...

What barrel length did you have it cut to?

[sidewaysil80]

I’m really liking the idea of the gas block insert. It seems like a bomb proof product and simple to install. Even though they are willing to replace the barrel, they have always done right by me in the past and I think that may be a little overkill for something that is just .004” too large.

What barrel length did you have it cut to?

10.3” for m193 and 70/30 suppressor use.

[markm]

I would never recommend welding a barrel.

We're talking about a stress relieved alloy steel pressure vessel, not a mild steel trailer hitch.

This.