The OP answered a question about the gun with the following:
Originally Posted by Wadesauce
It's .50 calibre, I can find out in the morning, maybe even post a picture if your interested
So, yes, he's trying to sell it. He doesn't have enough posts to do so in the BST forum, and selling in the regular forums is against TFL's rules. Closing the thread was appropriate.
That said, by all means PM him with your information.