Hornady 8th edition does not list any data for the 300 gr. XTP in either the rifle or revolver section. They do list data for it for ONLY the Ruger Blackhawk and the T/C Contender and they WARN not to use this data in ANY other firearms. Hornady does say that they would be ok in Marlin 1894S or the Winchester Model 94 but to start low and work up.
Hornady tested Lil' Gun, AA#9, Viht N-110,Win 296, 2400, H4227, and IMR 4227. Your titegroup would not be appropriate.
Lil' Gun--start 15.0- maximum 17.7
AA#9---------15.5-------max 17
viht N-110----16---------max 17.8
2400---------16.5-------max 18
Win 296------17.9-------max 21.7
H4227--------18.5-------max 20
IMR 4227-----18.7------19.5
Use this data at your own risk and follow Hornady's warnings!!