It definitely has a 9310 bolt not a c158 but i don't care. - Spikes Tactical M16 Bolt Carrier Group (BCG)

Great fast service like always from Optics planet. The Spikes BCG looks great. Some people are upset because they were expecting a C158 bolt and I can understand that since they're supposed to be mil spec. But it doesn't matter to me. 9310 when heat treated correctly is stronger than c158. The fit and finish looks great. Nice staking job. Chrome plating in the gas key and piston chamber looks nice. The bolt moves smoothly in the carrier. Not too tight or too loose. Just right. The best thing was the price. I feel like I got my money's worth. I'm happy with my purchase. Time and a few thousand rounds will tell the real story of the Spikes tactical BCG. I don't think it will let me down.