I am new to the rifle world. I mostly shoot handguns & shotguns. I joined a club that I now have access to a 25, 50, 100 & 200 yard range. So I decided to build an AR. Finished it last week and finally took it to the 25 & 50 yard range. It shot very tight groups but kept hitting low center. Any tricks on how to zero an AR-15. I am currently using magpul gen 2 front & rear sights. I planned on getting better optics but my wife found all the receipts for how it sits now. Let's just say I thought the 1st round was going to use on me (lol).