Ive done a lot of shooting out to 600 yrds. I never shot much further cause I never had a long enough range. Generally, on perfect days, I wouldn't be happy with a 3 shot group unless they were within a dime at 100 yrds, within a quarter at 300, and within an outstretched hand at 600. Thats an example of the kinda things that can go wrong after 350 or 400 yrds even with HP rifles. A 22 LR example like the ones weve heard hear doesn't surprise me that much. The real trick is "repeatable accuracy" not first round luck.
And as long as I have the distance lazered and the wind doped perfectly, like on an actual shooting range, I have no problems hitting targets at extended ranges with custom made loads, featuring big for caliber boat tail spitzer bullets with a high SD that translates into a high BC. I believe in accurizing any rifle I buy to whittle down its accuracy potential. That means trigger work, floating/bedding the action/barrel...ect The rifle itself is capable of amazing accuracy out to very long ranges. One of the most remarkable out of the box system is the Browning A-Bolt with a 24" barrel and BOSS accurizing system in .338 mag or one of the .300 mags.
I have found the Sierra Gameking SPBT hunting bullets the most accurate bullets of any kind. Even more accurate then the HPBT match type.