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Welding up gas port holes


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So I really needed more gas on my system, and kept enlarging the holes till they all broke into each other. 

 

I have contacted a local TIG welder who thought the holes were too big and filling may warp the barrel.

 

Any insight/input that would help this come together would be appreciated. Worst case scenario is I will put a band around it and call it good, but I sure would like to fill the holes. 

 

My layman thoughts:

 

Brass backer of course with tight fit

 

support/sleeve the barrel to prevent warping? 

 

Anyone who has done this know the temp/settings or technique that I could pass on to the welder? 

Thank you in advance. 

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Hey Cobra maybe I can just send it over to you?! You did such a good job on my Leftie charging handle I bet this would be a snap, right?big_smile.gif

 

Sorry bro, can't help you with that one yet unfortunately. Without an FFL I can only work on parts. Get a good local welder and as you said, a brass backer to maintain the barrel shape and keep weld from getting inside the bore. You shouldn't need to fully fill in the holes really just bridge the gap back, then drill a fourth port like really should have been done instead of enlarging the existing ones.

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Hey Cobra maybe I can just send it over to you?! You did such a good job on my Leftie charging handle I bet this would be a snap, right?big_smile.gif

 

Sorry bro, can't help you with that one yet unfortunately. Without an FFL I can only work on parts. Get a good local welder and as you said, a brass backer to maintain the barrel shape and keep weld from getting inside the bore. You shouldn't need to fully fill in the holes really just bridge the gap back, then drill a fourth port like really should have been done instead of enlarging the existing ones.

 

The barrel is not on the receiver...

This may be the first case where friction should be added instead of removed. Add material to the carrier, hammer, add some burrs to the rails, and chop the barrel. Lol. Good luck man, I'm sure all will be fine in the end.

Unfortunately even with the hole(s) this big its not enough gas. The barrel is too short so I am moving the gas ports back....

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If you are going to shorten up the gas system you had to weld these holes up anyway. Nbd. Just seal them up, don't burn off the chrome or drop any boogers in there! Would be safer with a brass slug machined snug to the bore. If you have to give the welder tips.....idk. But here goes. 40-50 amps. Needle sharp tungsten. Tig with a remote. Weld with the tip tangent to the barrel. So when he fires up, the flame should roll across the top of the barrel. NOT down into the barrel!!!!! The metal follows the heat. The heat is wherever you point it. Pretty simple. If done right your barrel will look like this. Lol jk

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How short is the barrel? (as measured off the bolt face).

 

It's very possible with a well profiled BCG & FCG like you have to go as short as 11" and still be able to cycle light loads without having to move the gas system. I've done it.

 

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I am happy with the 12.5" -  I have a Chaos Rail that goes over the top cover and mounts at the original gas block area. I really wanted to keep the gas in the same place to keep the rail mount available, but I am trying now to move the gas block back 2.25 so I can use the Tromix piston/tube (BTW how do you get the gas tube off from the piece that mounts to the trunion?)

 

I am then hoping to round up an additional gas block and mount in the original position, but cut the top off that holds the piston and just have it as a handguard mount. So if I fuck up the filling of the holes I will have the gas block hole sealed and just put it over the ports and call it good. 

 

If anyone has a vacant gas block I am interested - I have my feelers out and think I have one rounded up, but its not a done deal yet.  

 

I appreciate the help guys -  I have never done this before and am enjoying bumbling my way through it, and really dont have any expectation of success, but its happening and if it works I will be stoked!

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I assume you have access to a lathe if you are moving the gas block back. Why not just make a band/sleeve with a lug at the bottom and thread it for a common thread pitch? Buying another whole gas block just to chop it just doesn't seem like a very economical way to approach the project. Not my money though. Just a suggestion.... 


FINALLY!!!! Bigger is NOT better. Lol

Not in this case at least ;)

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I have access however no talent, and therefore am paying retail for the turning down and other machine services. I saw a gas block cadiz sold on ebay for $150. It costs more than $150 to have someone fab the part 1 off. If anyone here possesses the skill and ambition to do so I am interested in meeting you! I may shop it around a bit but the chop method was considered cost effective under the circumstances.

 

Edit: I slept on it and thought perhaps just a steel sleeve with a nut welded to it would do the job, and may move forward with an idea like that.

Edited by negev5021
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I searched a bit and found this AR10 gas block:

 

http://www.midwayusa.com/product/482126/doublestar-gas-block-single-picatinny-rail-ar-15-lr-308-aluminum-mattem

 

It may serve as a good start - I am imagining it upside down for the picatiny rail to act as the material to tap for the handguard screw -

 

I know its a half ass solution... but it just may work...

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