I take my AR with me when I leave the house every day, which means each morning I have to rack the chambered round out for it to be legal in the car. When you rack the round out of an AR a few times, the bullet will develop some noteworthy scratches (enough to feel with your finger). I'd be surprised if anyone here has any factual information about the effects of this, but I'd be curious to hear any scientifically-based reasons why people do or don't think this would effect precision ballistics.
Note, if these were XM193, I wouldn't care because they aren't precise anyway. I use MK262 Mod 1, which is MOA ammo from a good gun. I read that Sierra didn't even want to agree to put a cannelure on the SMK 77gr OTM bullet, for fear of degraded ballistics. But that they agreed to as it was a contract requirement. Knowing that, I'd think you'd loose something if the bullet is scratched, but I don't have a great sense of exactly how aerodynamics work right at the bullet. For reference, my gun will shoot sub MOA with these when they're fresh out of the box, so even a small effect would be significant by comparison.
Note, if these were XM193, I wouldn't care because they aren't precise anyway. I use MK262 Mod 1, which is MOA ammo from a good gun. I read that Sierra didn't even want to agree to put a cannelure on the SMK 77gr OTM bullet, for fear of degraded ballistics. But that they agreed to as it was a contract requirement. Knowing that, I'd think you'd loose something if the bullet is scratched, but I don't have a great sense of exactly how aerodynamics work right at the bullet. For reference, my gun will shoot sub MOA with these when they're fresh out of the box, so even a small effect would be significant by comparison.