[P-990]

The .22-250 would be "better" based purely on case capacity and velocity potential.

However! You're more likely to find a .223/5.56 set-up with a fast twist barrel (1-8 or 1-8) for tossing the heavier .224" bullets, say the 75-80gr match bullets. These bullets are far superior to any little 55gr pill past 300 yards, as they have higher ballistic coefficients. They bleed speed more slowly and resist wind better.

I've never seen a .22-250 on the line of a Highpower match, and I've seen pleny of other creations used. My guess is that whatever the .22-250 might offer, it isn't worth the trade-off in barrel life, muzzle-blast and powder consumption to a target shooter. If somebody is using a case that big, it's with a 6mm or a 6.5mm, which is better yet for downrange ballistics.

(FWIW, I compete in NRA and CMP matches with an AR-15 Service Rifle, .223-caliber, out to 600 yards. When the day comes and I "upgrade" it will probably be to a 6mm match rifle.)