I've done the "15 minute" trigger job on more than a few without issue but the key is to polish ever so lightly without removing anything but burrs.
Of course changing springs and actually firing the dang thing will do just as good.
Just don't ever pull a real trigger for comparison. I've used RR 2 stage and now a Geiselle G2S which is priced comparative to RR and have never seen a stock trigger anywhere close to either one. Spend the $130 and get a G2S, change the trigger spring to a stock spring if you don't need 4.5lb pull. This is the best improvement you can do for your AR.
