primer goes off but is all

[skeeter@ccia.com]

Ok so after 2 shots taken, the gun sat for the rest of the week loaded till season ended....upon cleaning the load at the end of the day, the primer fired but is all that happened. I know pirodex was added so is in there...question is:....when loading pellets one side has a taper...does it make a difference as to what end goes in first?.... I figure maybe the hole is plugged somehow but wouldn't a cap fire with enough force to ignite it? This is the breakdown HR 50cal that uses the plastic cap holders. I guess I should remove the plug and empty it that way.....thanks