The only comment I can make is that if the AB's didn't shoot very well at longer ranges, they were not going to shoot very well at shorter ranges either.
Another possibility is that you got a good 3-shot group at 100 yards with the AB's, and assumed that was enough of a test to guess what 3-shot groups would do at longer ranges. A single 3-shot group at 100 yards is about as statistically reliable as one bite off a corner of a burrito.
