The case looks so much like the 30X47 HBR they could be twins. You most likely could start low and work up to the 30X47 loads watching for signs of pressure. I have never shot a 30 TC or been around anyone that has but I can't see getting the velocity they claim unless they are using a powder that we reloaders can't get which is what they are most likely doing. I can get better velocity than a 300 savage but I am probably at a higher pressure than listed loads but I can not get as much velocity as a 308.
Here are some loads that are the best I can come up with for my 30X47 HBR. It has a 12 twist barrel 26 inches long and has a generous throat so you can load 168 gr Sierra Match Kings and not have any bullet base sticking down in the powder chamber of the case. I make my cases from Federal Match 308 cases.
Deer hunting load: 43 grs. IMR 4895, Fed. 210M primer, Fed. Match case, 125 gr. Nosler Ballistic Tip, 20 thousands off the lands. This is a DRIT killing load.
Deer load #2: 42 grs IMR 4895, Fed. 210M primer, Fed. Match case, 150 gr. Sierra Pro Hunter. 10 thousands off the lands.
Target load: 41 grs. Varget, CCI BR-2 primer, Fed. Match case, 168 Sierra Match King 10 thousands off the lands. This load shoots under 1/2 MOA at 300 yards.
Rifle was built over 25 years ago for hunter class bench rest on a trued short Ruger 77 action in a glassed Ruger wood stock, Canjar trigger (I think), and an unknown make CM barrel about like a #7 Shilen. The guy that had it made died shortly after receiving it and his widow just sold off all his stuff 3 years ago. It had a Lyman 24 power target scope on it he was using to start doing some load work up with cast bullets. He documented every shot he fired and I have the targets and information. He had only fired the rifle 100 times with 50 of those to fireform his cases.
These loads are for reference only, use at your own risk.