Group sizes dont always depend on the cost of the ammo. When you do the comparison of what you actually shot, you basically shot the same stuff. Regular brass, standard measured powder throw, standard 55grain bullets. Now take that and compare it to a box of match ammo that has much lower tolerances for differences in charge weights, brass weights, and bullet weights and spec, and you will realize the differences between match ammo and plinking ammo. The comparison you did was really just 2 different types of plinking ammo. Hopefully that makes sense.