If it's not selling and you're keen to move it on, make sure your ad is the best it can be. Your gun just isn't desirable the way you've presented it. For a start the backend is three times longer than the front, you get to include ten photos. At least show it fully retracted in some of those. If you have a garden away from prying eyes, take advantage of that and get some close-ups in natural light, so people can accurately assess the condition. Currently I'm lumping you in with all the others we see who've bought a gun off a mate, who bought it off a bloke on a site. You're not really sure what the base gun is or when the work was done. You don't even seem to realise that it's too powerful to be used, all this doesn't instill confidence in the prospective buyer.
If all that doesn't work, you should bring the price down incrementally. I could buy a brand new CYMA Platinum delivered to my door (you make no mention of postage), or several other mid to high-end RIF's, for what you're currently asking.
All the best.
