335 will be the fastest burn rate, followed by Varget them, 4064. If you look at the Hodgdon reloading site and match calibers up to powders, you can match up your bullet as well. I think the 335 maybe a little fast for the 243, based on Hodgdon's site, but I dont have any experience with 243. If you are just getting started in reloading, stay the heck away from Rumbler's loads - no offense Mike - but his tend to be pretty hot and you don't want to have a bad experience reloading.