My first AR build was a Heavy stainless ER Shaw barrel 1/8 twist. It will not shoot anything below 60 grains well, but shoots .5 on several heavy bullets. I was really wanting something to shoot 50 and 55 grain bullets. I built another ar in a carbine ctr package with 1/9 barrel and am very happy with it, although I've not tried to see what groups would be, only using red dot sights. My problem is which way to go with the heavy rifle. I don't like all the weight and the 1/8 twist. Should i change the barrel and keep everything else or go with a complete upper or upper without bcg. Just can't decide. I want it to shoot good, but in the 50 to 55 gr. bullets and be a couple of pounds lighter. What do you think?