What is you starting point? Sweet spot? I am almost finished with my 300wm build, 26' proof barrel and I used the reamer Broz promotes over at LRO. I have heard great things abt this N570 powder with the 215 Berger.
I've been running RE33 in my Lapua improved behind a Berger 300. I've shot it from 30° to 70° and haven't noticed any significant changes. LabRadar shows the highest to lowest velocity under those conditions has been 15-20fps difference. It's great powder. From what I've read, I think the trouble comes when ambient temps are above 80 to 85°.I know nobody seems to like it, but RL33 is another powder that is very accurate and matches N570 in velocity, but is not temp stable. I am curious if anyone has verified how unstable it is from 30 degrees up to around 90 degrees? Will a load developed in the winter blow the chamber up in the summer?