Gun parts have been prohibited on ePay for a couple of years. Due to ePay's stupidity, many gun parts are able to "slip through". Many times the sellers will list a barrel as a "ballistic tube"; a trigger, as a "release"; or a gas cylinder assembly, as a "front sight holder". The listings are endless and very imaginative. EPay's anti-gun crowd is either too naive or stupid to check. Also, no one wants to "tip off" the ePay anti-gunners.
Many parts still find their way onto ePay none the less.