And are they reloadable?

Steal? Aluminum? Try a magnet on it.

try a magnet looks like lacquered steel

shine a light down in the case mouth 1 hole or 2 for the primer flash hole?

so yes reloadable probably but not worth the work to do it , we have proven you can reload nearly everything but in a common case while not engaged in guerilla warfare it is a lot easier to find brass.

Nickel plated brass is my guess

Doesn't nickel plating embrittle the brass shortening reloading lifespan? I don't reload but I've heard that but don't know.

Looks like polymer coat steel casing. Most cases like that have a Berdan primer pocket. You can't reload them. That's my guess without having a look at the markings.

x2

I've seen two methods mentioned for popping those berdan primers. A special pin that fits the holes in that particular case and a hydraulic method using water and a plunger. Neither of which are doable on a large scale.

there is a method that looks like an old school can opener that punctures the berdan primer then pries it out

almost anything can be reloaded but steel is not worth it if brass is available

now if you have a bunch of old berdan primers and can cast projectiles and all your ever going to get are steel cases you can get a few uses out of them

but that is a level of guerrilla we needn't get into in the USA where we can get brass and boxer primers and make plenty up

you can also carefully convert berdan primer brass cases to boxer , it takes a sharp center punch and steady hand on the drill , you can punch and drill the old primer also taking out the anvil that on a berdan primer is formed in the case then a boxer type flash channel , I wouldn't use them for full pressure loads but it is a way of turning old 7.62x54 brass into reload-able cases to use with boxer primers and send reduced loads from those cases

as to the question about Nickle plated brass , it is a thin layer to give corrosion resistance and lubricity to the extraction it doesn't seem to adversely effect brass life significantly