As far as I know, there are no real online courses.
There are several correspondence courses.
NO prospective employer will hire someone with those kind of credentials.
People who hire gunsmith's hire people with PROVEN training.
That means military training, (and not just standard "armorer" training), or people who attended the good gunsmithing schools, or who served an apprenticeship with a recognized master gunsmith who's know to turn out competent people.
Correspondence courses are for hobbyists, not pros.
This doesn't mean you can't develop the skills, but this is much more difficult to do, and employers will quickly pass over you for people they KNOW have the right training.
If you're looking to hire a computer expert, you hire one who has a degree from a recognized college or technical school, not the guy who took a mail-order course.
Same thing with gunsmiths.
