when you move into 500 yard + ranges, it's time to put the 22's back in the safe! Your now moving into the world of the big sixes and the 6.5's. A 22 centerfire will at be almost as good, but never the equale. My 6mm/250AI will shoot 105's out to 1000 yards rather well (a lot better than I ever thought it would). I've dropped several coyotes in the 650+ yard range, and would never attempt that with a Jaybird. Yet as good as that was I also know that a 6.5 is another rung up on the ladder.
I have a couple buddies that were in the forefront of the 6/.284 craze. They used to send me pictures of 750+ yard kills, and I just drooled at the photos!! Later one of them told be he went thru two barrels a year! And he had something up his sleeve. It was a 6/.284, .100 short. Now I'm interested! He says he can see no loss in velocity by shoving the shoulders back .100", and keeping the overall length the same. Well to take it another step further his buddy pushed the shoulders back .156 for no serious loss in velocity. But he has six hundred rounds thru the barrel, and all is well. Both of these guys shoot Berger 88's almost as fast as Berger can make them. It would be interesting to see how many grains of water those cases held when compaired to some of the others out there.
gary