xThough a little spendy, Eley Match, EPS, and Tenex EPS is very accurate .22 lr ammo.
This is five shots at a 100 yards from a Calfee XP-100 that I just re-barreled. My son's Anschutz 1907 Match rifle, and his Anny Benchrest rifle will both put 10 rnds under an 1-1/2" @ 200 yards when the wind is minimal. We have also had really good results with Lapua ammo.
The standard velocity ammo will yield better accuracy at long range than the high velocity ammo. -You don't have the transition from super sonic to sub sonic along the way. We have shot out to 550 yards with the .22 lr's with suprising accuracy.
Steve, didn't you pick off a couple of prairie dogs lately (410 yards) with the .22?