I won't argue about if anything is necessary or not, Just present what is the most consistent method for me. I go to great lengths to cut great threads, square and smooth surfaces, Chamber finishes that improve the function of grip and at the same time extraction, precise head space every time so I want the best results when making up a barrel.
While conducting the barrel test, I used a chrome moly receiver and a stainless barrel to avoid the gaulding that can occur when using Stainless to Stainless makeup. To avoid scuffing the threads I used a light gun oil on the threads the first time so the test would have the best chance of being consistent and reprasenitive of any differences. After torquing to 75 pounds I then match marked the barrel to receiver with a zero stamp to get two alignment points and improve the consistency of reading the orientation in degrees.
From then on, a different thread lube was used with a thorough cleaning regiment to remove any existing lube, and then apply the next lube to be tested. Using the match marks an inclinometer was used to measure any differences in rotation. Each lubricant was tested twice for consistency to itself.
The last test was with dry threads (No thread Lubricant) and with the torque the same, it made up with the least rotation and the second test rotated less than the first with some signs of scuffing on the threads. This would likely ruin a stainless to stainless makeup and could/ would gauld and ruin the assembly of the two parts, so dry Is never recommended. using a good thread assembly lube, the assembly of like to like materials showed similar results.
A bit long winded, but a test is only as good as the effort put into it and the results in differences.
There were more parallel test ran to find other differences, Like the amount of torque used, and i will comment on this a little also.
Using less than 35 ft/lbs the consistency fell. using 75 ft/lbs was very consistent with some thread assembly lubes. when we approached 100 ft/lbs of torque we had good consistencies, but encountered some tenon stretch that actually altered head space slightly even though the tenon threads were 1 1/16x16 and the torque was well below the tensile strength of the material. these differences were not a problem but they did prove that there is a point that to much torque can change the loading and is not necessary.
So the procedure discussed earlier Is the way I get the most consistency with all different thread pitches and shank sizes and the assembly lube I use is not affected by heat or solvents So It is my choice for all barrel assemblies even though it may be overkill to some. If I were going to build a switch barrel system I would definitely use this system because of its repeatability.
J E CUSTOM