Man, thats the reason I steered clear of the 1187 was seeing so many people with that problem. Definatly return if possible. I have shot mine about 40 shots with no problem like that. But sounds like a possible chamber issue. Sometimes, while chambering, at the factory, their tooling can become wore down by 2/1000ths or so at the end of cycle. If that happens, chamber can be too tight. Have you tried anymore ammo or another brand? Maybe try 3" just to see what it does. I was told not to oil the peice attached to the reciever that holds the shells and the piston slides onto. I feel for ya. Let me know how it gets resolved.