My 444P likes the 265gr Hornady Flat Points and the 300gr XTPs.
Reduce and work up as needed.
REM brass trimmed to 2.220"
Rem 9-1/2 Primer
46.5gr of H4198 with a 265gr Hornady FP (4300 discontinued) seated to 2.560"
This load is over Hornady listed max but under Hodgdon max.
39.7gr of H4198 with a 300gr XTP (44280) seated to 2.535"
This load is Hornady max.
Both loads are crimped with a Lee FCD 3/4's of a turn past contact.
Both loads will make 5 shot groups around 2-1/2" to 3" at 100yds. POI is about 3" lower at 100yds for the 300gr XTP if I recall correctly. I think I have Chrony data for the 265 but I never did the XTPs. I'll update if I can find it in my notes.
I've never been one for cast or PC bullets. The 444P is Ballard rifling and is supposed to perform better with cast loads than the older Microgroove barrels. Handloader #224 Aug 2003 lists some cast loads using RL-7.
Attached FileHandloader Digest 10th edition has a rather dated article on all kinds of funky loads for 444 Marlin. This article is available online if you dig around. It has a 236.5gr SWC GC load using H335.
Attached File Attached File