RK 57 witch Frame

[DONDon1]

Well I got this RK 57 and I am not sure about the Frame B ore C type ?
The core is magnetic.

[DONDon1]

some more pictures

[DONDon1]

some more

[Matthieu]

Rather unflawed to be "B" frame, so definitely this is "C" frame.

[Ghocking]

A nice RK, as Mathijs has said, not a B, as no knee flaw and dipping ring, C frame, and very nice too 👍🏻

[Nigel N]

Indeed a "C" frame...the bleed flaw on the 9 o'clock arm is unique to that frame(though not on all!) it also has the remains of the dent row on the 3 o'clock arm, and a magnetic core, so should be no later than mid 70's, and probably quite a few years earlier.
-Nigel