I have been using the data for Encores or other SS pistols chambered in 308.
Hodgdon has a decent listing of loads for a 15" barrel which use the same powders as the longer tubes but also has some differences in the loads. Worth a look.
The best grouping loads I have for mine so far have been using H4895, and Barnes 130gr TTSX. These were worked up for my grandson to hunt with and ew started at the minimum youth load and have worked up to 42grs so far. Load runs just over 2600fps and shoots just under an inch at 100yds for me, and he has done pretty well with it him self.
I mainly use factory Remington or what ever else I can find sheap and on sale. When I tried to duplicate the factory load I never got groups closer than 2" at 100 so pretty much gave up till the grandson wanted to start hunting. Sort of just got it back from him after two years of being his dedicated rifle. Hopefully in the not so distant future I wlil hit something that shoots well with it.