I don't know what kind of ammo you've got, but most of the surplus 8mm is pretty powerful stuff. The 8mm"JS" loadings used in the 1898 Mausers and variants are about equal to the .30'06 in their proper loadings. In fact, the development of the 8mm Mauser JS prompted our boys to scrap the .30'03 in favor of the .30'06. It's a real performer. Smokeless powder gets more potent with age, so the old stuff may actually be a notch more powerful (something to watch out for on well-used rifles). The Turk I throw out of my Yugo Mauser kicks even harder than the Swedish Norma hunting loads and burns a 1' to 2' fireball in the air. It's corrosive, of course, but what a show! I haven't measured it, but I've heard it gets up to 3,000 fps.
Keep in mind, the American loadings are all crap. SAAMI decided to prohibit domestic factories from loading to JS levels for reasons which stopped being relevant 75 years ago. Get the Swedish or Czech stuff for your good ammo, and surplus military for your practice stuff. This is one area where it's a good idea to favor our European allies.