Great news...the 243 and the 270 like very similar powders.
If you run mid-weight bullets (~80 gr in 243 and ~130 in 270) you can run them both well with H4350...
If you run heavy-weight bullets (>90 gr in 243 and >140 gr in 270) you can run the both well with H4831SC....
Moral of the story, watch gunbot for an 8 lb jug of one of those two to pop up and then buy one powder for both and don't look back. Using this method will also help mitigate the Hazmat fee.
