I sold the 444 long ago. I could not find written records, I probably lost it on an old computer that failed, but I found a couple of targets:
444 Marlin, 265 grain Hornady, 45.5 grains IMR4198, 1.05 MOA
444 Marlin, 310 NEI (cast - no gas check), 42 grains RE7, 11.46 MOA
I suppose that Hornady bullet would have worked fine. I wanted a cast bullet shooter and I couldn't get heavy cast bullets to work well. I know I shot a lot of loads through that 444 but these were the only targets I could find.
There’s more knowledge these days and more mould options too. It wasn’t all that long ago that most 44 moulds were primarily designed for 44 mag revolvers and these have different SAAMI specs to 44 mag rifles. Rifles generally have larger groove diameters and slower twist barrels.
The reason you couldn’t achieve decent accuracy with cast in your 444 was likely soft alloy (for the speed), no GC or the bullet diameter was too small. Any of these reasons can results in poor accuracy with cast. I was at my wits end with my B92 in 44 mag trying get it to shoot cast. B92’s in 44mag have rifling that is similar to Marlin microgroove barrels, ie shallow multiple groove rifling and a very generous groove diameter. After I cracked the code it would match or exceed jacketed bullet accuracy.
