416rigby
I would go with the bought cast projectiles with a gas check, but size them down to +0.001" your groove dia with a push through LEE sizer, much faster than casting etc yourself & less overall effort for you.
The Red Dot load that Eagle27 talks about is a hidden gem, about 1400fps & very accurate too!
Only problem is it shoots 7" high from my normal full loads - but that's just my rifle.
I'm working on a new replacement front sight for the light loads & a QD mount for a small Red dot sight, hope lovey don't find out or my goose is cooked - budget a bit tight at present, had the replace all the tyres on the truck this month!
I had my own CZ .404 bore checked (.423" groove - ordered off CBE a mould & sizing die 0.424" to suit), this calibre is a bit harder to get over our way. More time & effort to do so for me but I enjoy the challenges of reloading!
My ultimate aim in reloading.....loading BP in a double rifle!
Worth it in the long run getting these old / oddball cartridges going again!
All the best
93x64mm