RE: 243 WSSM
I have a 6mm and a 243Wssm. Ive had plenty of luck with 90grn BTs in the 6mm but its in an old 788 which I dont like very much so I had to get something new in that great caliber size,
Ive loaded some 85 grn Nos Part with 45 grns of Rel19. Its shooting <1" groups so far so good. I havent had time to try much else out yet other then factory stuff.
Be careful the 45grns is above max so work up to it. I just received an email from Vitha Vuri on loads they finally worked up with their powder if you want some info on that. I have IMR and Hogdons load info. Also have loads from Hornadywith Alliants powders let me know if you need any info.