That's good that whatever was done is working for you.
I don't care how guys go about modding their rifles, inside the box or outside. What I care about... For some dumb reason that escapes me and keeps me posting is... Bad advice from folks that leads others to screw up their rifles LOL
I'm not trying to be an ass here, I'm merely passing on what I've learned over the years and hope to help save others from some of the mistakes, pit falls and plain ol waste of time stuff that I experienced along my journey.
Having professionaly unitized 100's of chinese and american made assemblies and tuning/repairing/accurizing/custom building a few hundred M14 type rifles from norinco to LRB ect.... We looked for solutions to common issues that the platform, regardless of manufacturer, suffered.
Gas port alignment and the fact that norinco gas locks aren't availlable meant doing away with shims, thus roll peening the gas band shoulder for custom fit.... To many, this IS an out of the box solution to the need for shims.
Then, knowing if we sent a guy his fresly unitized assembly.... He would probably need to shim.
So what did we do, we looked again for a solution. A full shim, kinda tear drop shaped with 2 holes, just llike the gas band. Designed to go between cylinder and band, and providing as much surface area contact. Yes, this did work, but it was fugly and we went back to the standard and accepted method of unitizing, coupled with roll peening that shoulder forward.
Why mess with a good thing right?
