Does anyone have or know where I could look up ballistic charts for a 16" AR15 with a 1:9 twist for 55gr. .223 rounds? I am trying to decide if I want to zero at 50 or 100 yards. I would like to get a ball park of the trajectory, so I can save the ammo for fine tuning not guessing. All the info on .223 that I have is for a 24in barrel. Thanks for the help.