What were your H110 loads?
I have no experience in loading for a short fat gun like that but....
Not sure what H110 load you used but I bet you know H110 doesn't like to be down-loaded (loaded light). If memory serves, it's not recommended to run more than 3-5% under with H110. Yes, 360-400 grainers are big bullets but you'll need a lot of H110 to make it go. I would have to ASSume 23-24 grains?
Online data shows a 180 FPS difference in 21 vs 24 grains of H110 but a pressure difference of 19600 CUP!!! To me this means you have to find the sweet spot.
I haven't heard many people that prefer LG over H110.
Hodgden's data for a 360 in .454 with LG is out of a 9 3/8" barrel....a much different animal than you have.
Pass the gravy.