How much?

[thechozenone]

would it cost to have a gunsmith weld the carbine port and drill a mid length port on a barrel.

Thanks....

[Gunsmith Dan]

Welding directly on a barrel is something you do not want to do unless you absolutely have to and had the equipment to re heat treat the barrel.

Cheaper and better off cutting off the section, threading it and adding a extension (i.e. muzzle brake to keep the barrel at 16" +) then drill the port hole in a new location.

[ar15barrels]

would it cost to have a gunsmith weld the carbine port and drill a mid length port on a barrel.

Thanks....

Most barrels will step down in diameter about 0.020" just forward of the original gas block location.
This causes a problem if you want to move the gas port forward to the midlength position.
There are some barrels such as the CMMG multi-purpose barrels that retain their full 0.75" diameter at the carbine, midlength and rifle length gas port locations.
Almost any other barrel will be an issue.
The solution which works for most 0.75" gas block seat carbine barrels is to turn the front of the barrel into a lightweight barrel.
Then you can use a 0.625" gas block at the midlength position.
I can mechanically plug the old gas port and properly locate and drill the new gas port.

[kcstott]

He did ask how much to do it properly.
But as Randell mentioned there is more to it then plugging the hole and moving the gas block.

That said the last thing you'd want to do is reheat treat the barrel. Barrels undergo a special process that includes stress relieving. The is nothing wrong with a small plug weld over a gas port. Sending you barrel to a heat treat shop runs more risk of it coming back screwed up then anything let alone the cost is enough to warrant buying a new barrel.
But again a small weld done properly well not hurt your barrel in the least.

[wpage]

There are no guarentees and pricing is impossible without pictures or added data...

[killmime1234]

How much heat would it take to cause tempering isuess? I ask because I did the opposite of what the OP is asking. I cut a mid length back to carbine, plugged and welded the hole, then used some Kragen's ceramic header paint, that required heating the barrel to 400F, to cover the exposed steel.

It hasn't had issues yet. Should I be concerned?

[kcstott]

At the typical hardness that a barrel manufacturer reaches in heat treating and tempering You would have to exceed 1000 degrees for at least three hours to remove the temper.

This is why i say that a small plug weld if done properly will have no noticeable or measurable effect on the barrel. It will not distort it, it will not warp it, it will not affect it in any way that can be measured by your average shop or shooter.

Now if you want to get down to the actual facts. Yes it will affect the heat treat in the HAZ (Heat affected zone) it will change the hardness and the stresses located in and around the HAZ.
The question is will it make any noticeable difference. NO and I'll bet you a barrel on that one. Again though "If done properly".
we are talking about plugging a .078" hole. How much heat do you need???

400 Degrees is not going to hurt a thing.

[killmime1234]

Thanks. I'm glad to hear it.