Bear Creek Arsenal complete upper M4 profile 16 incher, 18 shots fired

[rickt300]

I guess I could justify two uppers of similar configuration if I put night vision on one and leave the scope on the other! I also ordered 500 rounds of the Wolf steel cased cheap stuff. The Bear Creek Arms people say they won't honor their warranty if this ammo is used? Is it the bi metal bullet? What if I pulled the bullets and replaced them with a standard cup and core?