Cast you will be limited to what the lead alloy can stand. I dont typically use fancy hard alloys, nor do I water quench to harden as dropped from the mould, so my cast bullets usually are running less that 1450fps. So many of the old traditional calibers ran about 1250fps with lead bullets so between 1000 and there is a nice place to start playing with them.
Once you get some experience with them behind you then you can think about if you really want (or need to) to try to push them faster and how to do it.
Be advised that your point of impact will change dramatically requiring good notes and repeatable sight/scope settings to avoid re-sighting in every switch.
FWIW, at one time I got into making 'light' and 'heavy' loads for my calibers; ie, plinking loads and hunting loads. Lots of messing about and trials and shooting fun, but came to realize I really only tended to use one load most of the time and HATED changing the sighting for each. Then I hit upon having whatever load I liked per gun and if I 'needed' more beans just go up in caliber. Thats been working out quite well for some time now as I have the advantage of having several rifles to choose from.