I shoot IMR 7828 and 117 grain flat base Sierra's In my 257 Wby. I have been using this load since 7828 was released in the early 80's. American Hunter Magazine listed some early loads for all the Weatherby line up and this is their listed load for 117 at 70.0 grains. The only change I have made is 7828 ssc, instead of standard long cut 7828. I have some loads made up to test N570 with 133 grain Elite Hunters from Berger. Haven't fired any yet and it will be a ladder up for accuracy and pressure results. I add .5 grains and just load two rounds. All came from Quick Load. N570 is sure a PITA in the powder measure. Every charge I throw bridges in the Harrell's powder measure.