Coaxial resonator at 500MHz...1GHz

I want to use a coaxial resonator as the IF filter at 500MHz. The resonator will be made of copper, with no special treatment, maybe not even silver plating.
What selectivity can be expected from this?
The frequency stability on the long term and with temperature variation of 10-40°C is good enough for an IF filter, or it needs to be tuned periodically?

copper or brass will oxide in the air and the thin layer of oxide is not good conudctor.

Thanks for reply.
So silver plating is mandatory.
What about frequency stability in time and with temperature variation if silver plating is done.

So far i read the chapter about coaxial resonators in Microwave filters - Matthaei, Jones.
The diameter ratio should ensure a 76ohm impedance for minimum loss, and the structure will be silver or at least tin plated.

What is the simplest software you recommend for simulation? The main problems remaining are:
- temperature stability;
- size of the magnetic coupling loops.

By the way, this is not a commercial project, given the huge size of the filter.