I had an extra upper/lower and decided to put a 6arc together, this is just a range gun. It has a 20” barrel and been looking at Druid hills ammo, 58 Grain Hornady V-Max , 75 Grain Hornady V-Max, 90 Grain Hornady ELD-X. Should I just buy all 3 and see what does the best or does anyone have a opinion where I should start? Thanks