a .22 is best for squirrel IMO some like shotguns for that tho. as far as your mossey as fore mentioned you need to provide more info if you want better responses do you want to learn how to hunt i think you should come right and say that as i would be no help there as i do not know anything about hunting.however there are alot of people on this forum that would be more than happy to help guide you to the places to get started on that and where to find the support you need as far as the serial number it should be on the left side of the trigger housing above the action release button. i wish you well and hope you don't give up on us ...just be more specific in you questions. there are great folks here and welcome to the firing line forum
