Sorry to be so rushed on you. I am going shooting out of town in the next few days and bought ammo but need to know if it will work in my RRA Tactical CAR A4. I got American Eagle Tactical 5.56 (5.56 X 45mm) or something similar. Will this work in my RRA without hurting it, me, etc??? I learned they have higher pressures. Any info will help. Thank you so much!