There is much more wrong with black tip bullets than some pull marks.
I did a test with some 7.62mm black tip bullets and my accurate AR10A4. This rife turns in consistent MOA with good ammo if I do my part.
The first thing I found was that the weight and length of the BT bullets was the most inconsistent that I've ever measured. I selected the most similar examples and segregated them by groups for testing. The brass used was measured for concentricity. I tried both stick and ball powder, in weights that are known to be generally accurate for gas guns.
The group results were dismal. Crowds with lots-o-flyers. I stopped testing to rethink how I will respond to this reloading challenge, because I didn't want to "test out" all the bullets I had only to be left with a magazine full at the end. After all, BT bullets for the 7.62mm are no longer for sale! I'm thinking of plating them with moly, to give them more consistency launching in the barrel, and settling on a ball powder and retesting, with the aim of achieving marginally acceptable battle accuracy, + high speed for penetration. I feel like I have to proceed though, because on some future occasion it might prove really lucky to have BT bullets loaded for a 7.62mm gas gun.