+1 for Oregunner
You really should be able to send this gun back regardless of what the seller, or Gunbroker says about it. You are completely correct that it is a safety issue. I remember from my college days in pre, pre-law, that the UCC or "Uniform Commercial Code" was a book written about federal guidelines for interstate commerce. There was a portion of that book that spoke about
"Warrent of Merchantability" that basicly stated that if you were to sell anything, lets just say it is a Duck, for instance, that it had to walk like a Duck, quack like a Duck, and do all things that could be reasonably expected of a Duck. No matter what the warrenty says about this or that, these rules override anything that is written. so you should have good ground to stand on.
If there are any real Attorneys at Law reading this, please correct anything that I have said in error, as I am not one, I do not portray one on TV., shoot, I have not even stayed at a Holiday Inn recently!
But that should give you a right to relief in this situation. And frankly if you are given any grief whatsoever about this issue, I would come on TFL and state the problem, the name of the seller, and how you were treated by Gunbroker! Unless of course the TFL does not allow that type of thing. But you certainly should be able to get relief from either Gunbroker, or primaraly, the seller.
Of course, that is JMHO, andas always YMMV.
Willy