This is old 7mm Mauser UMC ammo. I pulled them today.

173gr RN and 34gr of Cheerios powder.

What powder might that be?

back in the earlier part of last century they had a number of donut shaped powders.
lightning was one, but...
lightning number-2, no-60 and maybe no-80 would all be suspects at that amount, with that description, and a 140-175gr. bullet.

thanks for sharing -- i think the only modern donut powder is trailboss, but no clue on what was loaded back in the day