I bought a set of these and have done some bolt actions but never any AR's.
http://eze-lap.com/products/diamond-hone-stone/
I also bought a trigger pull gauge to measure starting point and finish results.
http://www.midwayusa.com/product/220725/lyman-trigger-pull-gage-electronic-digital-0-to-12-lb
Hope that helps, be safe!
