With a 1/9 twist barrel I get 1" groups at 25meters (just a bit less at 25 yards). I can keep the rounds on a 6" New Bold Target disk at 50 yards.
I've seen 1:12 twist barrels (the old M16A1 rifles) shoot 1-2" groups at 50 yards.
Added Note: These things were orginally intended to allow you to shoot on indoor ranges (typically 50feet to a max of 25 yards). For that purpose they work fine.