The Parker ballistic extremes are a very good bullet. Knurling the bullets for sabotless takes alot of extra time. Especially to make them right and consistent.

BH209 is a lot better powder then you give it credit for. RB was really doing a lot of research on it trying to figure why and how it was so good. It still shot the light bullets extremely well when the other smokeless powders would not.

Your ULA with 42grns of N110 and a 275grn Parker BE
will do the job on most animals with out a doubt. No need to change the bullet and it works. When i get mine back, i plan on trying the ULA with the 275grn Lehigh. If they dont shoot well theres always the 277grn Lehigh bullets. I think both will do just fine with the Short Black harvester sabots.