What’s your draw back with bushmaster and the others? I’ve made several sub moa rifles using bm lowers and model1sales complete uppers over the years. Those uppers paired nicely with the lowers. The anodized finishes matched and they’re tight. Both my colt sp1 and delta hbar are so loose I use an accu wedge every blue moon or so when I take them out to shoot. Just wondering because I don’t use my AR’s for pin point work I use my bolt action rigs.