03/14/2020
PART 2: 7.62x39 UPPER BUILD
In Part 1 of the series I told what my intent was on the Upper project, I had unboxed the parts to be used and went over where all the different parts had come from for the build. Now lets look at the barrel and I will go over what I do with ever barrel I use on a build. First I examine the barrel inside and out, check the chamber, check head space, check the bore and crown, along with muzzle threads if there are any and last but not least how it looks cosmically. If I find and issues that I can not fix myself, the barrel is not used and goes back, I use a Hawkeye Bore Scope to inspect barrels and chambers. Once I decide the barrel is good to go, the first thing I do is check to make sure the barrel is dimpled for the gas block set screw, if it is not then I dimple the barrel with a fixture, I have seen all price range of barrels that did not have this dimple, it is very important to keep the gas block from walking forward over time , and this happens a lot on factory guns and builds, I have had many brought to me because the gun wont cycle and this was the culprit. After the dimple is taking care of I mount the upper receiver in a fixture and slide the barrel in place, then I blend the feed ramps on the barrel extension in to the feed ramps milled into the receiver , this little process makes many of the calibers the the AR was not designed to shoot function flawlessly. Now I use a caliber specific Flex-Hone brand hone to clean up the chamber , I use a 400 briefly then a 800 grit, but remember you do not want you chamber polished like glass, it can be to slick and cause problems. Once I have done every thing to the barrel, I give it a good rub down with 000 steel wool and Hoppes 9, this makes those chalky rough barrels look nice. Part 3 will be assembly.
