One thing to learn in the process is the fit upper to lower, matters not unless you are trying to win matches or shoot 1000 yards with the gun and even then it doesn't make much difference.... at 300 yards its under a half inch difference in overall 10 shot group sizes, actually I think it was less than that but I can't seem to recall
You can always just throw in an acu wedge to tighten things up too.
