Daniel Defense qpq's the barrel assembly, and then re torques the barrel extensions, I presume they remove, clean threads, torque.
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Daniel Defense qpq's the barrel assembly, and then re torques the barrel extensions, I presume they remove, clean threads, torque.
Hmm...I didn't know Daniel Defense did the treatment in that order. Seems a little backward for them. It is possible to re-torque the barrel extension back to the proper alignment with the gas port but after being treated I was under the impression it would be hard to get the correct torque spec. Maybe I'm wrong.
From what I understand, getting the port to line back up after removing the extension is a pain even without QPQ.
"If force can take away liberty, force is necessary to preserve it. It is the hatred of violence alongside the willingness to use violence that preserves liberty. In order for us to live as free men, we have to hate the violence that takes away liberty, yet at the same time, we must embrace the violence that preserves it. That is the paradox our founders appreciated and made work for over 200 years."
-Christopher Brownwell
So evidently they drill the gas port after treatment as well.
Not sure why they wouldn't just treat the barrels and extensions separately like some do IIRC. It seems like it would be more beneficial for the barrel and extension threads to get the full treatment.
I'm curious if they believe it to be a corrosion issue or potential for the extension to loosen.
"If force can take away liberty, force is necessary to preserve it. It is the hatred of violence alongside the willingness to use violence that preserves liberty. In order for us to live as free men, we have to hate the violence that takes away liberty, yet at the same time, we must embrace the violence that preserves it. That is the paradox our founders appreciated and made work for over 200 years."
-Christopher Brownwell
Not that I would rely on this but the two main companies that do salt bath nitride assure me there haven't been any issues with treating assembled barrels.
"If force can take away liberty, force is necessary to preserve it. It is the hatred of violence alongside the willingness to use violence that preserves liberty. In order for us to live as free men, we have to hate the violence that takes away liberty, yet at the same time, we must embrace the violence that preserves it. That is the paradox our founders appreciated and made work for over 200 years."
-Christopher Brownwell
I used the Nitrider (no, not David Hasslehoff) here in Phoenix who does POF's Rock Creek Barrels. They are all done with the extensions on. He said he had never heard of POF having any problems but maybe for the few that do come loose, POF just isn't notifying him.
http://www.cttaz.com/
Last edited by Swatdude1; 04-16-13 at 22:41.
How do you go back through several hundred extensions and match them to the barrel they came off of? There is a stamp, caliber and twist on the top of the barrel not to mention headspace where the extension is matched to a single barrel. I do hundreds of these barrels every month...unless like now every company is backed up 5-6 months. We have always treated both, removed the extension, cleaned the threads, retorqued, drill gas port.
Stainless extensions and stainless barrels treated together do not come as loose but I'm not going to take a chance and not remove and clean the threads.
AR15performance
TRUMP 2020
The 6.8 is the best choice for hunting deer and hogs with an AR15.
Ahh. I was under the impression headspace could be set with mix matched barrels and extensions. I see your point that would be stupid after treatment.
Is cleaning the threads more a corrosion issue or loosening issue?
For a stainless barrel...say your extension is torqued and port is already drilled. Before melonite, could you remove the index pin, take a flat end mill and drill further down into the barrel threads about .020" then press a longer index pin back in place?
Then when the barrel gets melonited, remove the pin and extension, clean the threads, and re-torque the extension until the pin hole lined up with the hole in the barrel threads? This way you solve the loosening problem with a pin stop and you're able to clean the threads and re-torque to the right index.
Is there the chance it could then torque under spec because of the friction reducing properties of the melonite?
"If force can take away liberty, force is necessary to preserve it. It is the hatred of violence alongside the willingness to use violence that preserves liberty. In order for us to live as free men, we have to hate the violence that takes away liberty, yet at the same time, we must embrace the violence that preserves it. That is the paradox our founders appreciated and made work for over 200 years."
-Christopher Brownwell
In my experience they will not line back up perfectly unless you torque to the point and disregard the torque value. If the extension wobbles on the barrel no matter how small, the accuracy will be terrible since that barrel extension is the only thing that connects the barrel to the receiver.
Years ago while on the road I had a 308 barrel made by a smith in the south west. The first 10 shots were great, near 1/2" at 100. then after that they just kept getting bigger. The barrel was loose in the extension. It could not be repaired without installing a new extension that was clocked early then the shoulder turned down to make the pin aline the gas port then the chamber recut to the proper headspace. I use an impact wrench to torque the extensions. Trying to hand tighten them in a vice, even a 80lb round part vice doesn't work.
AR15performance
TRUMP 2020
The 6.8 is the best choice for hunting deer and hogs with an AR15.
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