This bullet I have used for many years and has shot excellent groups for me for many years but sometimes we chase higher BC bullets thinking we are doing better. This bullet is a sledge hammer on deer and other critters. Works well in my 30-06 and my .308. In fact I have let many people at the range shoot the load I worked up in my .308 and it would always shoot under 1/2" in their gun at 100 for 3 shots if they could shoot. 5 different 308 rifles and all shot like that. It is a mild load. I went shooting today testing loads at 200 yards with 155 A-Max and the 165 Game king HPBT That is Hollow Point Boat Tail (HPBT). Lapua cases Varget powder CCI 200 primers .002" neck tension 165 game king set at 2.680" over all length NO crimp. You ask what amount of powder.. well pick an amount that you like is almost good enough. But I usually had 41.5-43.0 gr and it has worked in many different brand cases. Here is a ladder test I did today at 200 yards with the HPBT bullet. Shot #1 was from a cold barrel and each shot after that to shot #7 was chambered as quick as I could get back on target ..so about 30 seconds between shots today. And off the top of my Corolla again with front bag only. Shots 1, 2 and 3 = .950" center to center. Those 3 are the lower loads but hot highest on paper. Those loads were 41.5 gr , 41.8 gr. and 42.1 gr. All loads were .3gr steps for my ladder. Shots 4, 5 and 6 were .608" center to center. 42.4 gr. , 42.7 gr.and 4.30 gr. of Varget. I think I will load some 42.5 and see how they do. Shot 7 was all alone in Lala land. I think maybe a bad case. These cases are not sorted to how many times fired and not weighed..They are 3 different lot # of cases. Yea I am bad. But I did neck turn them. OD is .334" and ID is .306". Before neck turning some measured .3345 to .337" OD, Figured I would neck turn. Here is the 200 yard picture from today. I also shot some 155A-Max bullets in Winchester cases and Lapua cases. 1.265" was the best 3 shot group at 200 yards from any of those loads. And they printed 4" away from this load in the left hand corner of the target.