ID and Questions about some rifle cartridges

Hi all,
I have some questions about the cartridges shown below.

No 1. what does STC mean?
No 2. Is this bulgarian??
No 3. when, where and by who?
No 4. when, where and by who?

Any information about these is welcome.
Perhaps they are very well known, but I am absolutely out of my field, being a shotshell collector.

many regards rené

  1. Swiss 10,3 Schuetzen rifle Cartridge, made by Munitionsfabrik, Altdorf, Switzerland (Cross)…STC???
    2.Bulgarian, Khazanlik Ammunition Factory,( Voenni Fabrika “B phi”–War Factory) 8x56R “S” Cartridge, 1940 mf, Berdan 5,5mm, Corrosive Primed, German style Flake Rifle Powder, 207 grain FMJBT
  2. German Made (?DM?) 9,5x60R Turkish Mauser, Black Powder cartridge, M1887. (“Big Mauser”)
    [b]4.Siam, (Thailand) Type 45 (RS 121–1902) Mauser Design Rifle made by Koishikawa Factory, Tokyo. Cartridge very similar to Austro-Hungarian M1893 8x50R cartridge, except for some minor Dimensional differences.

Doc AV[/b]

#4 edited on review of Photo.

1- it is a date code STC = 1975

Hi DocAv and Pivi,

Many thanks for the quick answers!
Are these ones hard to find. Or just common?
This just for interest because they are a gift for a friend.

Regards rené

#1 and 2 are pretty common. I have seen the same Turkish cartridge sold for 20 Euros or less