If ever unable to remove a stuck projectile by attempted pulling or air chuck. There is another method. Change out your nipple with a small straight grease fitting use in automotive purposes. Pump grease into your barrel with the use of an Plews automotive grease gun. The hydraulic action will move many stacked over charges. I push a barrel for a friend once with grease that had 4 charges and projectiles built up in it and left many years in that condition. The penance you pay for using grease is cleaning the barrel itself which you can do by hand or blow out with air. Otherwise that little CO-2 gizmo thingy usually works most of the time in the field or at home to remove a mistaken charge or two. If putting rifle into long time storage. A barrel pumped full of grease is the best one can do to keep rust at a minimum or nonexistent in a bore.
"Do not follow where the path leads, rather go where there is no path and leave a trail for others to follow."