The moly-coated 139gr 280 Light Mag (green labeled box) is the most accurate factory ammo I have ever shot.
I got my 280 handi back in December. My area range doesn't open till April, so I won't have grouping pictures till then, but I have shot my gun out at the farm a few times. It will break clay pigeons on a dirt pile EVERY SHOT at 325 yards with the light mags.
I have it set up to aim 6" high at that distance, so I figure its zeroed at approximately 50 and 200 yards.
The chrony showed 3130 to 3145 out of the 26" barrel, which like you suggested is definitely in the range of some 7mm mag ammo.
I can't wait to get this gun on a good bench rest and see if it can do 100yd cloverleaf groups.