Red Dead Redemption Free Roam Hackers?

I see people all the time in Free Roam that ride horses in full sprint up and down hills that never miss a shot at me. I actually killed one guy and took off on my horse so when he respawned, he wouldn't be able to kill me, but this persistant nutsucker came after me. I pulled off the trail, took out a sniper rifle and waited for him to come over the hill. When he did, I shot him three times with it, but in full sprint on his horse, he shot me three times with a volcanic pistol and killed me. Is it my imagination, or is something wrong here? It's almost like his targeting recticle auto aimed to me. He must have killed me 20 times when I respawned and I couldn't leave the area until I somehow killed him.....by shooting his horse and then proceeding to beat the **** out of him afterwards until he killed over.