I always use 175 grain RN for those old 7 Mauser single shots. they were made for jacketed bullets, not lead.
In the late 80's, I came into a Belgian Champlain in 7 Mauser, about a month later I found some "Red Lable" (pre–WW I) Remington Ammo for Rolling Blocks. 175 grain Copper-Nickel jacketed ammo (about 400 rounds) when I reloaded for that gun, I used Hornady's Jacketed Soft points and IMR 3031 powder.
It is amazing what those FMJ's did to the head of a ground hog! The sights were so crude I had to be within 50 yards for a target that small.
Ivan