I've had some extremely accurate rifles built on 98 and even 96 actions. If you are using an ex-military receiver, just be aware of what you have. Some are better than others, and some are very questionable. So look closely before you begin and avoid anything that looks like it was used hard and put away wet by someone's military or was previously bubbafied.
See PO Ackley's tests.
WW1 era rifles have had 100 years worth of use. Inter-war and WW2 era, 30's and early 40's up to 43 are usually very good, but I would not use a late war German 98 on anything higher pressure. Many of the Turkish actions are so beat up and loose that I would personally avoid them as well.
So, best case scenario in my book would be a Czech or german action made between the 30's and 1943.