Originally Posted by Brd_Hntr
The method used to check is a plastic coated rod with a taped mark on the rod. The rod is inserted into your empty magazine tube. If the rod goes in past the mark you get a citation. Simple, but effective.
The requirement is "...the plug must be of one piece construction incapable of removal without disassembling the gun."
Yes, I have had my shotgun checked in the field.
Last time I was there when they were checking, they had a bendy spring device with a brass end that went up the tube, and the spring had a mark on it.
I offered the warden my over/under to check, and he seemed peeved for some reason..