eb,
I thought that sounded a little slow

. Mine is also 1-9 twist. The folks at Bushmaster told me that with a 1-9 twist rate, that using bullet weights of 45gr.-75gr. would give me the best accuracy.
My elderly neighbor actually bought the same exact rifle as mine. He was sighting it in yesterday at 25 yards. He shot 3, five shot groups. Two of the groups made one ragged hole. Needless to say he was very happy. One of the groups was the first five shots ever fired out of his gun. (other than any the factory may have fired)
MH