To determine the best .22 LR match ammunition for your rifle, purchase one or two boxes of the ammunition brands and quality levels you wish to examine. Research online, as ammo manufacturers have plenty of information (especially muzzle velocity) that you can use to pinpoint the specific .22 LR match ammunition characteristics you are looking for.
Next, go to the the local rifle range on a clear, calm day and set up a suitable target at 50 yards. Shoot from a bench using a solid rest. Fire five fouling shots first, then begin your record strings. Take your time and make each shot count. Fire at least five groups of five shots each, then measure the extreme spread of each group and average the results (add them together then divide by five). Clean the bore of your rifle thoroughly and repeat the process with other brands and/or loads. After you identify one or two brands which are superior, retest only using those.