True, nickel-chrome is not ferromagnetic.
Neither is a metaloxide layer, nor a carbon resistance track, a ceramic body, tinned copper or alloy leads.
The carbon composition resistors do not have end caps.
All of the carbon film resistors i have do not seem to have nickel-ferro end caps.
I know Beyschlag(Vishay BC / Philips BC) makes/made 2% accurate carbon films that look almost identical to the metal films they produce.
One way of finding out could be to check the TK value.
Regular low power metal films have a TK of 50, carbon films are in the order of TK = 200.
Yageo MF series have a TK of 25.
A reason for not using carbon films.
Any one of you have an idea how to check the power rating of a resistor, 1/4W, 0.4W, 1/2W, 0.6W, without having to destroy it ?