Is all ammo good to use/warrantied in your rifles/uppers?

We test our uppers and rifles with U.S. military spec brass cased new ammunition. With so many variations out there (quality level, pressure levels, etc), we will only warranty them with new brass cased ammo. We do not warranty our uppers or rifles with reloads or steel cased ammo. Furthermore, please take caution in knowing what ammo is safe to shoot in your gun. There are many different .223 and 5.56×45 loads on the market, and the manufacturers of such ammo do not recommend all of them for every AR. For example, Hornady Performance Match 5.56 NATO 75gr BTHP is only recommended for AR’s with a rifle length gas system. We take every precaution to ensure the safety of our customers, but please take the time to research and buy quality ammo that was made for your gun. If you have any questions, please contact us.