Either bullet would be fine. I would be more inclined to stick with the 180s but 170s would work just the same. Reloading manuals will be slim on info but an internet search will reveal various loads. Ammoguide.com has some great info and more than likely be the only source you would need. Good luck with your antique and hunt with it as Pap did.
Thanks for the information. I have an old 99 in 303 and recently ordered unprimed brass(Prvi Partisan) and some 180 gr. Hornady round nose Interlock tips. The reloading data will give me some place to start reloading for the old gun.