Doesn't have to be a good magnet. Does have to be good wire cutters, if you do that.
You need to read your club's rules. If it says no AP, you may be ok with steel cored ammo. Not all of it is AP. If it says no steel, you're SOL anyway. Highly unlikely that some RO's will know that steel core doesn't always mean AP though. Do not get into a peeing contest with any RO. He owns the range while on duty.
Reloading will make the whole issue go away and you'll be shooting better ammo.