I just got my first gun, and it's and ar 15. I'm trying to figure out what I should do to it. Its a DPMS .223/5.56 Sportical. I want to get an optic, but i have no idea what to get. My price range for the optic is 300-450$ tops. I want an optic that you can use at 25 yards, but can also be used at 200 yards. I also want to know what you guys think the best collapsible iron sights are for the ar. And on my gas block the rail is shorter on the front than the rear. Do you guys think that would cause a problem aiming down range? Thanks for your guy's help!