I had a few of these back before I disposed of my collection;
https://www.flickr.com/photos/312284...7607964699940/
At the time I found a German website with mainly military and sporting ammo on, but it was archived by brands, so the Utendoerffer brand had a few pellet tins included with all the powder stuff, I recall they were stated to be prewar and as mentioned are great colourful items especially on the base,with all the gold medals etc.
They had a huge company range, a bit like a German Kynoch dating back to 1855 then acquired by RWS, and their stamp can be found on every type of military and hunting pistol and rifle ammo.
I never did nail down the exact age recall was 1930's but don't quote me after all this time!, but German sites are the place to look, I just wish I could recall the one I saw. Link below which has some interesting photos;
http://www.patronensammlervereinigun...ts_archiv.html
Google H.Utendoerffer Kugeln and see what occurs as a starter
ATB, Ed