If the spring that is used to keep the mag catch in place is damaged/missing/non-operational then it won't matter what mag catch you install, it still wont work correctly. You need to check that the mag catch is being returned to where it needs to be to hold the mag in place properly by the spring first. If this is not the cause of the fault then a metal mag catch may work. It cartainly shouldn't cause any problems due to it being worn down over time!