10,5 x 33 mm?

HS = R.W.S
Bullet Ø 10,5 mm
Case lenght 33 mm

What might this be?

Looks like a 10.1x33R RWS Cattle Killer - need all case measurements to be sure.

Thank you:
Case measurements:
Mouth: 10,9 mm
Base: 11,7 mm
Rim: 12,7 mm
Primer, some 5,8 mm
Any further information I can provide?

That looks about right although the base is generally 11.3-11.4mm - rest matches.

Here is some info on it:

Most interesting, thank you. I have used a lot of different guns and heard of a lot more…, I have never heard the term cattle killer. Is that some similarity to todays bolt guns or humane killers that use just a blank and a
bolt fixed to the device?
I found an article of such units from a NZ museum page. Interesting!

I think it may have been Greener who coined the term. At least he had a .310 Cadet cartridge with the headstamp .310 CK. (Cattle Killer).
As you say, same idea as the newer humane killers.