Raimey - You are correct, it is “13”
Thank you Raimey & Mike for your excellent insights and knowledge. I find it fascinating learning more about vintage firearms!

As for bullet choices, Ammo Seek lists Sellier & Bellot 193 grain bullets as the only option I’m finding. I’m assuming these would be fine?

https://www.targetsportsusa.com/sel...2ra-p-112799.aspx?trafficsource=AmmoSeek

As for Emil Eckoldt marks, I don’t see any more hearts (that was a great catch, Raimey!) but I did notice what might be a “E K” in a circle on the water table - see below. Or maybe that’s for something else?


[Linked Image from jpgbox.com]