I'm not brdeano, but I'll take a shot at that question...
While it's not possible for a rifle to shoot a physically smaller group (excluding "operator error", of course), it isn't at all unusual for some rifle to print smaller MOA groups at longer range.
I've had several loads in several rifles that would print only 1" (1 MOA) at 100, but open up to only 1.25" (.625 MOA) at 200.
The type of bullet you shoot can make a difference, also. Normally, flat base bullets stabilize quicker, hence their popularity among 100 & 200 yard BR shooters. They do not, however, hold up at long range as well as a boat tail, which takes a little more distance to stabilize, but holds on better at longer ranges. Hence the preference for boat tail bullets among long range benchrest shooters.
While I'm naturally interested in what my pdog loads do at 100 yards, I really consider the 200 yard and 300 yard groups much more important and informative.
Mike