My original quest was to find a load that worked equally well in handgun and rifle. And with lead there is the issue of the kind of rifling in the barrel of the rifle.
Ronin, I've been using coated 240gr MIssouri Bullet LSWCs as my .44 Mag companion round. At 18 Brinell, they're on the harder side and since they're coated, they tend to act a little like a jacketed bullet, which (in my humble opinion) allows me to get a way with using them in the bigger SAAMI bore spec of the rifle. In my case, I found that the rifle shot a 1.25" ragged hole at 21yds (unbenched/unbraced) with anything that the revolver grouped at 1" or better at 7 yds. I experimented with HS-6, H110, 4227, Blue Dot, Universal and 2400. 20.3gr of 2400 gave me the best accuracy for a true magnum load. I haven't chrono'd the revolver yet, but the 20.3gr of 2400 load averaged 1751fps.through the 20" barrel of the rifle.
I had a chance to mess with my brother's .44 Mag companion guns, as well and while his rifle isn't shooting as tight (brand new gun), I'm starting to believe, when trying to get a single companion load, it's better to identify 4 or 5 "best of" loads for the revolver and apply those to the rifle to find what works best. Just my 2 cents. Good luck!
