A friend of mine at work as a Bushmaster Carbon 15 97s and the left feed ramp has a small pit in it. This causes the point of the bullet to lodge in the feedramp, jamming the rifle.

He just sent the upper back to Bushmaster to be fixed.  This sounds like a heck of a thing to get past Quality Control.  Anyone else hear of this happening?

I had a Bushmaster barrel with a small burr in the feedway ramp that cause the rifle to malfunction.  The nose of the bullet would get stuck in the feedway ramp every so often and had to be knocked loose with a finger.  First time was at a rifle class at Frontsight.  Initially thought it was a type 3 malfunction, but couldn't clear it .  Sent it back to Bushmaster and they de-burred the ramp and haven't had a problem since.  Hope this helps.