New to rifles and confused...

[wbm]

So, if I replace the stock should I expect an accuracy improvement?

Usually that is the case unless the rifle has accuracy issues.

How did the rifle shoot at the range? Do you reload or just shoot factory ammunition?

If you shoot factory, I would suggest you get a box of Federal AR223 50gr Tipped and try it.

Just shoot the rifle a lot! Then you will then have a pretty good idea of what the rifle is capable of, the kind of ammunition it likes and your own shooting capability.