Barrel extension wear FYI

[redmist]

I just had this happen to a Melonited barrel as I was taking a comp off. And I mean hardly ANY torque! I probably could have done it by hand.

I am thinking the melonite process annealed that extension.

[Joe Mamma]

I just had this happen to a Melonited barrel as I was taking a comp off. And I mean hardly ANY torque! I probably could have done it by hand.

I am thinking the melonite process annealed that extension.

I think it's simply the very high temperatures which are part of the melonite process which require the extension to be torqued afterwards. As someone pointed out, AFTER the melonite/nitride process, the extension needs to be torqued and then the gas port should be drilled so it is aligned properly.

I know a lot of people don't retorque the extension or drill the port after the melonite/nitride process. I think a lot of this has to do with the "we haven't had a problem yet" doing it the wrong way syndrome. As more and more people find out about these problems, the industry will catch up and pretty much everyone will be doing it the right way.

All of that being said, there are companies that do this process (melonite/nitride treatment, barrel extension tightening, and gas port drilling sequence) properly. So I only buy my melonite/nitride barrels from these guys.

Joe Mamma

[mtdawg169]

I've never seen the inside of a worn out extension. Is that wear typical for a higher round count? Or should it never look like that? Absolutely seems excessive for 4k rounds, but it got me curious about extension wear in general.

[constructor]

I just had this happen to a Melonited barrel as I was taking a comp off. And I mean hardly ANY torque! I probably could have done it by hand.

I am thinking the melonite process annealed that extension.

I'm thinking the extension wasn't hardened to begin with. We do 10s of thousands of Melonite treated barrels. I've seen 1 like that. The rest of the extensions are hard.
I asked Burlington about this 7 years ago. They said the Melonite process at 1200 degrees would only drop the C scale 1 point. That's bringing an extension from 60 down to 59.

[Junkie]

I think it's simply the very high temperatures which are part of the melonite process which require the extension to be torqued afterwards. As someone pointed out, AFTER the melonite/nitride process, the extension needs to be torqued and then the gas port should be drilled so it is aligned properly.

I know a lot of people don't retorque the extension or drill the port after the melonite/nitride process. I think a lot of this has to do with the "we haven't had a problem yet" doing it the wrong way syndrome. As more and more people find out about these problems, the industry will catch up and pretty much everyone will be doing it the right way.

All of that being said, there are companies that do this process (melonite/nitride treatment, barrel extension tightening, and gas port drilling sequence) properly. So I only buy my melonite/nitride barrels from these guys.

Joe Mamma

I know this is an old thread, but...

Is there not an advantage to drilling before nitriding? I would expect a nitrided gas port to resist wear better, and therefore last longer.

Obviously it's important to have the torque to the extension right. Just trying to figure out if there's a valid reason to do them in the wrong order...

[Col_Crocs]

It would be, as Phreakish stated in the BCM barrel thread. Look up his post, it's very informative. I wonder if it'd be possible to torque the BE on, port, remove, nitride then put everything back together afterwards. I know this creates atleast 4 additional steps to the manufacturing process but all that aside, I'm curious if it's at all possible.

[Leaveammoforme]

I know this is an old thread, but...

Is there not an advantage to drilling before nitriding? I would expect a nitrided gas port to resist wear better, and therefore last longer.

Obviously it's important to have the torque to the extension right. Just trying to figure out if there's a valid reason to do them in the wrong order...

What I assume is you stand a chance of the gas port being in wrong location if you torque extension, locate gas port off of it, remove extension, heat to crazy amount then reinstall extension. Extension may not end up in same exact location as before.

[Col_Crocs]

I was suspecting that to be the case... So does that mean the extreme heat brings on some sort of dimensional change? If so, how does that affect the bore?