I don't think your in the "real world."
He most certainly is. Your gun is a crudely sporterized military rifle. It just doesn't possess any particular desirability that would justify the price you're asking. It has no collector value and would be of most use to a hunter or shooter. And at the price you're asking, it's very possible to buy a used Remington 700 Classic or NEW Ruger 77 in that caliber with a little cash left over or for $200 or so more a Kimber Montana. I think you'd be lucky to get $400 out of that rig. That's reality.
You'd think someone who lists their occupation as "retail gun sales" would understand that.
