You want a gun related job and you don't want to be poor? I don't think there are that many options
Gunshops? Seem to pay minimum wage usually.
Security? Unless you are ex-military or a cop it seems you usually have to start in unarmed security (lets see, you are looking for trouble, wearing some kind of uniform and if you are lucky you are carrying a flashlight and pepper spray- no thank you). You may be able to get armored car guard without experience but that seems to be pretty backbreaking work, and not a lot of money. It also seems that most of these jobs don't pay that well (maybe low $20s with some experience).
Military? How old are you? What is your physical condition? Most aren't much different from civilian jobs, though you may get to qualify w/ a pistol and/or rifle once in a while and occasionally go out and play w/ one. Or you can go MP, infantry, armorer, etc to deal w/ guns more often. Money? With a college degree (and if you are young enough) you can become an officer and money isn't bad. Enlisted, you don't make much but many of the benefits can make up for that (GI bill, if you have student loans already sign up for 3 or 4 years and the Army will pay $60K of your loans, VA loans, etc). You could also use this background to get better paying jobs and better jobs generally in security.
Become a gunsmith. Well, there are few good ones, but there are tons of smiths out there. Once you take the training courses you will need to build a reputation and that may take a while. Most smiths seem to do it on the side, and there is a reason for that.
Work for a gunmaker. Well, they are companies with the needs of any other company. So you can do marketing, sales, PR, accounting, etc. for a gunmaker and at least be in the industry. But will you really have any more contact with guns than if you did the same thing for Ford?
For a comfortable paycheck, and living and working around firearms directly the best option I see is police work. Around here starting salary for most localities is upper $30s and even $40K+. With some experience you can do various specialties that may make the job more interesting or give you even more guns to use (SWAT for instance). With a degree and experience you may even be inclined to go into federal work (Secret Service, FBI) which really does seem to pay pretty well. You could also go into various security jobs on the side or after leaving and do it in a better job and for more money than most others going into security.