Probably an egg shaped BB lodged in the barrel with 5 or 6 BBs behind it. Step 1 empty chamber of all BBs. Step 2 open action, fully cocked with lever extended. Step 3 Hold gun upside down and tap stock on ground to dislodge the 5 or 6 BBs from the barrel, empty each one from the chamber as they come out. Step 4 Use a thin long rod (wire coat hanger worked for me) to ram the odd shaped BB back down the barrel and remove from gun like the last few. Step 5 refill and shoot.