I stalked. Looks like you just built yourself an AR and are a new shooter?

I like to write AR rounds as .223, because it conveys the bullet size a bit better, and helps people understand that the .223 bullet itself isn't much bigger than a .22 bullet. God damn that sounds condescending, sorry.

Anyway, the rifle is good. It doesn't kick much, and should be a lot of fun to shoot. They're pretty simple rifles overall. I personally would suggest loading 1 round the first time you pull the trigger. That way you test with the least possible variables, and if something goes wrong you can't have any unintended bullets going down range. Then I'd repeat it with 2 bullets, and 3 bullets. Once I get to 3 I generally figure it's time to load my magazine as full as the range will allow and test the magazine. I also might like to do a mag dump if given the option, just to run a few rounds through and see if it works fine fast, but a lot of ranges frown on that.

Make sure you understand the 4 basic rules of gun safety. Make sure you understand the 'manual of arms'. Make sure you understand the 4 basic rules of gun safety. Make sure you understand how to clear a jam. Make sure you understand the 4 basic rules of gun safety.

Your rifle will be kind of loud indoors, but you can't control what other people bring, so I second/third/etc. the suggestion to wear over-ear muffs and then shove in some disposable plugs too. Better to use and not need.

Make sure you understand the 4 basic rules of gun safety.