http://www.spoilersguide.com/the-mentalist/season-6-episode-8-red-john-sneak-peek-1/

Thats a sneak peak for next weeks episode . Janes final trick. Why does jane needs lisbons gun as a prop? Ill tell ya what the heller i know lol. Jane already has a gun yes? Jane knowing that red john is lisboning to him (listening) jane explicitly asks for a gun so red john knows. Jane had already planted his gun in the church. When red john faces him he/she will think jane had one gun and jane like he said to lisbon he will not use her gun. He doesnt he uses it to loose it maybe in scuffle who knows . Just when rj thinks he has em buck buck hes dead . "Jane you said you wouldnt shoot anyone ? -lisbon. Jane- " i said i wouldnt use your gun so its not a lie" haha i can see this happening ...