Lots we don't know here. Could still just be light loads or a poorly tuned rifle.
If the weather cooperates tomorrow I am going to try something to see if I can find a solution to my issue, I have a Rock River Lar 15, it ejects cases from just about everything I shoot at least ten feet or more, it will put 10 empty cases into a 24 inch circle. I am going to take the upper from my Build and slap it on to the Rock river lower, if the cases eject farther then I would assume the problem is with my lower, possibly the buffer spring, if nothing changes then I would tend to think it's the upper, I took the BCG apart and removed and cleaned the extractor, the extractor spring looks fine.
Ejector spring controls WHERE the empty cases land... FWIW.
Went out earlier this morning, new spring did not help, called on a friend of mine who has built a few AR's, we took the Bolt carrier group from one of his AR's and tried it in mine, cases ejected with no problem. When we took my BCG apart he noticed that the gas rings were not aligned correctly, correct that and also installed an O ring under extractor spring, will go out Tomorrow and see if that fixes the problem.
I went out earlier today and shot a couple of different loads using the lower from my Rock River Lar 15, cases ejected much farther even with AA2520, went to a gun shop and explained the situation, buffer spring replaced with one that is two inches shorter, will go out and see what happens tomorrow.
