This is some information that the ADI sent to me (their email information service for reloaders is slow but effective) for loading the 303 with ADI powders:
The Lyman cast bullet book has more data using Hodgdon powders, some of which are just re-packaged ADI powders. Trailboss is also a very easy powder to use with cast although will only provided low velocities. For medium velocities with cast I really like AR2206H (called Hodgdon 4895 in the USA), following the Hodgdon 60% rule;
https://www.hodgdon.com/PDF/H4895%20Red ... 0Loads.pdfI have not reloaded for 303 but have had good results with AP70N, Trail Boss and AR2206H and cast in the 30-30 and 308.