It's so hard to ship ammo for an individual that it will be just as cheap to order it from someplace like Grafs. I ended up buying a brick of several (yeah that's kind of expensive) different brands/tier levels and lots. If I found something that didn't shoot very well I sold it at our local club meet to someone like you wanting to try different brands to see what shot best. Hopefully you find something cheaper than CenterX that shoots well. And hopefully you can find a brand/tier level that is consistent from lot to lot. Some guys are trying different lots then going back and ordering a case or cases of that same lot. I really didn't want to have to order a case to get the most out of my rifle.
Yeah tactical panda, I was hoping that CenterX wouldn't shoot the best. It was painful to pay $12 a box of 50 for the stuff.