I found H 1000 a little too slow in my A1 though there may be a little room for heavier charges.
With 150 Nosler BT's 63 grains only got 2706fps.
154gb Hornady and 63gns chronographed 2673fps.
160gn Accubonds and 62gn generated only 2573fps.
Because I was 1-2 grains heaver than Rel 22 charges in the same weights which were generating much faster velocities, I moved on.
Also tried Retumbo but that too, was way too slow for the little A1 in .280.
John
