03-08-2020, 08:16 PM
I going to jump in on this one. This barrel was produced probably 4 years ago before we discovered that the nitriding process can reduce the torque required on the barrel extension. For the past 3 years to there abouts we send the barrel to nitride before installing the barrel extension and drilling the gas port.
Using a reaction rod seems to aggravate the situation. Barrels that would probably last for 1000's more rounds are being loosened by this method. We used to use the Reaction rod in our shop quite a bit until we had this happen on several barrels in one week from several different manufacturers. Most of these were from suppressor attachments that were rock set on. We now use another system that works better.
The extension pin is for alignment only.
Its not simply a deal where we can reinstall the pin because re torquing will place the timing of the alignment pin and the gas port about 5 to 10 degree off. We have to go through our batch of extension and try to find one that will match the barrel. Being the barrel is nitrided we cant just recut the chamber by .005 to match the gas port.
Unfortunately in this barrel's case none of the 100 extension we have in house clocked at the right place so we need to wait for the next batch of extensions next month to check if any of those will fit. If not we will discard the barrel and replace.
Mark Hostetter
Precision Firearms
Using a reaction rod seems to aggravate the situation. Barrels that would probably last for 1000's more rounds are being loosened by this method. We used to use the Reaction rod in our shop quite a bit until we had this happen on several barrels in one week from several different manufacturers. Most of these were from suppressor attachments that were rock set on. We now use another system that works better.
The extension pin is for alignment only.
Its not simply a deal where we can reinstall the pin because re torquing will place the timing of the alignment pin and the gas port about 5 to 10 degree off. We have to go through our batch of extension and try to find one that will match the barrel. Being the barrel is nitrided we cant just recut the chamber by .005 to match the gas port.
Unfortunately in this barrel's case none of the 100 extension we have in house clocked at the right place so we need to wait for the next batch of extensions next month to check if any of those will fit. If not we will discard the barrel and replace.
Mark Hostetter
Precision Firearms
"Precision - The Pinnacle of Perfection."