What would be the reaction equation between ammonium nitrate and a powdered metal? The SDS for ammonium nitrate says it will react with powdered metals spontaneously. What would be the reaction equation, say with iron or copper?

This mixture is used in various pyrotechnics, and it is intentionally allowed to combust with heat and shock, but how does the reaction proceed spontaneously as described in various SDSs in the absence of any ignition source? Is this due to the mix attracting small amounts of water, allowing the nitrate to attack a metal instead?

Would the theoretical products always just be various oxides of the metal involved?
I'm betting they mean that you can inadvertently make an explosive (technically a blasting agent) or highly flammable mixture by mixing powdered metal and ammonium nitrate.  I used to be a hard rock miner many centuries ago and was well read on explosives.  Aluminum powder and ammonium nitrate is a classic solid rocket fuel and industrial blasting agent/military explosive, for instance ammonal in bombs.  Ammonium nitrate/aluminum powder mixes (magnesium works, too) have better explosive properties than the usual mining ANFO (ammonium nitrate/fuel oil) mixtures, but the latter are preferred usually since ANFO is less expensive.

While blasting agents technically need a booster explosive to detonate, they will burn ferociously.  I'm guessing when a writer of a SDS sheet talks about powdered metal and AN, they are thinking about the potential of creating an extremely flammable mixture.

I looked at some MSDS for ammonium nitrate, and I see powdered metal listed along with reducing agents as incompatible mixtures.  Could you post a link to the MSDS you are reading?  I'm interpreting 'incompatible' as referring to explosive potential and not to a slow spontaneous reaction.

EDIT:  Well.  The usual metal powders that react with AN used in mining and explosives are aluminum and magnesium, so that is all I considered.  However, a bit of research shows that powdered zinc does react with ammonium nitrate, as in this video (note that it didn't actually ignite until set afire, but it definitely reacted).