Wrong bullet weights, IMO. For competition given you have a quality 1/7 twist don't make much sense not to shoot the bullets best fitted to your rifle barrel.
Why give up wind drift ya don't have to......
Suspect the 77grn SMK will be your best choice in the Krieger and Midway USA sells the BH bluebox 77 for a decent price.
YMMV, but my list is short here: there's BH which you have listed and then there's Federal Gold Medal 77grn SMKs.
ETA - forgot one, my personal long range AR15 load:
Sierra 77grn. MatchKing
24.0 grns. Accurate 2460, (Hot Load), DO NOT PUSH
loaded into once fired (or new) Remington Brass
Remington 7.5 small rifle benchrest primers
These are loaded mag length - 2.250" + or –
Come-ups for 24" Colt Accurized Rifle (6724) w/ Leupold Vari-X III, 4.5x14 w/ turrets and Mil-Dots
200-1 1/2 min
300-3 3/4 min
400-5 1/2 min
450-7 1/2 min
500-9 1/4 min
550-11 1/2 min
600-12 3/4 min
700-17 3/4 min
900- no target
1000-35 1/2 min (34-36 depending on humidity)
This may be of some use to ya.
What distance and type of competition? That makes a huge difference in your choices.
Anything under 200 - and I'd say you could use 52gr HPBT's which would be a much cheaper load. They will still cut your numbers in half from milsurp given those requirements, but the 68/69gr loads will buck the wind a bit better.
I think you are on the right track. While I agree - for your 1:7 twist barrel, the 77SMK's are nice - I dont think this is the application where they will be required. You are looking for ammo that will increase hit potential on a 8" target at 250yds. Given that's your longest shot... and 2MOA will get you there, I'd say looking at the BH in 52, 68, or 69 will do fine. 52 of course is the cheapest.
I wont shoot Ultramax... too spotty a reputation.
Georgia Arms 68's would likely be an excellent candidate for this... if economy is important.