I don't shoot in matches but do bench rest my AR-9s (4 of them) at 100yds.
My experience has been that at 50yds 1-10 twist barrels do just as well as my 1-16 twist barrel. Loads that hover around an inch for ten shots at 50yds very rarely go under 3 inches at 100yds from my 1-10 twist barrels. If they do it is not repeatable and always a handload, never factory. I've had six of 10 in a ragged hole at 100yds but the other four opened the group up to almost 4 inches.
My cheap ($100) 1-16 twist barrel is the lightest of the bunch and if it shoots 10 shots into an inch at 50yds it will put the same load of 10 shots into 2 inches or just slightly over at 100yds. I've done this over and over with loads as heavy as 147grs.
Next I'm trying some 158s.
My theory is these pistol bullets aren't built with quite the same degree of precision as our rifle bullets so the overly fast spin of the 1-10 twist will always show up any imperfection in the bullets at longer ranges. Just my observations with the 6 barrels I've been testing (over 5000 rounds this summer). One of those barrels is on a friends AR-9 and the other is on a Ruger PC carbine.
If anybody is interested the most accurate factory or reloaded ammo has used Remington BJHPs (Golden Saber) and Speer Gold Dots so far.