I am loading for a 3006 ABolt II with a 22" barrel. I had previously found that 180 interlock over H4350 was most accurate going on 2550 fps. This year I used the same brass and primers but tried H4831 and 180 gr Northforks....exactly the same. Up to 2550 the grouping got smaller to about an inch and then started to open up with a dramatic increase in recoil. I found this to be quite surprising. But, this rifle is most accurate with smaller bullets too. The personality of a rifle is an interesting thing.