Re: 280 Ackley Improved with H-1000
I used Nosler data for my 280AI with 160gr AB IMR-7828 start 57.5gr @ 2856fps to max 61.5gr @ 3043fps they used a 26" long Wiseman barrel 1/9 twist. If you look at Hodgdon data for 160gr AB they max out at 58gr/IMR-7828 @ 2849fps and they use 24" long barrel 1/9 twist.
My 280AI with 27" barrel with 60.5gr/IMR-7828 and 160gr AB @ 3058fps and 56gr/R-17 @ 3046fps.
I've had 4 boxes Berger 168gr VLD seating around here couple years just haven't tried them. I guess should pick up copy of Berger manual see what they mention.
Hodgdon data does seem slow but your not shooting 24" long barrel either so you may see increase in velocity with start load.
Well good luck