The topic of ammunition is of endless importance to Smallbore Prone Shooters. The lower priced match ammunition is actually quite good. That is stuff like Eley Club, RWS Target, SK Standard Plus, Wolf Target. These brands are much, much better than what you can get at Walmart. The mid grade stuff, like SK Rifle Match and Wolf Match Extra, is a little more consistent. All my lots of Green Tag are absolutely horrible.
What you will find with all grades of rimfire ammunition that the stuff varies by lot. One lot of Eley Black box may shoot like a house a fire, the next, just OK. The Eley representative at the National Matches said you only have a 33 1/3% chance of finding the best ammunition for your rifle without bench testing the stuff. Both Eley and Lapua have US test facilities for lot testing rimfire ammunition. I have used the Lapua. I was very surprised at how much variation there is, in my gun, between lots of the same ammunition, which was Center-X and Midas plus. I talked to a shooter who placed 2nd at the National this year, his Anschutz has been lot tested maybe 90 times, and he said, ammunition that shot well out of the bench rest fixture, did not necessarily shoot well in the prone position. Ammunition has to be tested as you will shoot.
What I have found, as well as others, is that the higher priced ammunition is more consistent than the lower priced. The expensive ammunition is tested at the factory. Flyers happen in all types, it is hard to know if it was you or the ammunition, but in my experience, the higher priced ammunition will have less flyers. The manufacturer's of premium priced match ammunition extensively tested the stuff at the factory, the higher priced stuff was the most accurate out of the factory test rifles. Eley said that is how Eley sorts out Tennex versus Match (Black Box). These are made in a special production line and under very stringent production controls. Eley Club and Target, they said a different production line for that ammunition. I have shot thousands of rounds of Club and Wolf in practice, or at matches where the results don't matter, and, every so often I get outstanding results, clean the targets, but, in the long run, a shot creeps out! The most noticeable problem is low velocity eights. A round in perfect alignment with the X ring but about four inches low at 100 yards. I begin to trust a particular lot after firing a brick of the stuff without any wild shots.
Champion Shooters
http://www.championshooters.com/ind...category&virtuemart_category_id=37&Itemid=111 will sell you a sampler, a bunch of boxes of different lots, and then, having tested them all in your rifle, you can buy a case of the best stuff.