Heavy ball would be a closer approximate to the ballistics for the sight. The 7.92x57 198gr ball is around 2500fps out of a 23.5"barrel while the 7.62x54 180gr ball is around 2700fps out of a 29" barrel. Light ball 7.62x54 150gr is around 3000fps. Good luck finding heavy ball, though. I haven't seen any in years.