The issue with 4320 is its kinda bulky, so you may fill the case before getting the velocity you want. No a big deal for all, but palma shooters need a 155 at at least 2950 fps, with 3000 better.
Varget is made in Australia and Hodgdon is the sole licensed distributor in the US. Same for H-4350. H-4831SC and some others as the attached pdf from ADI shows. Shipping and demand are bears at times.