People commonly quote Marx communicating that the possession of firearms must not be infringed, but I'd like more general principles and justifications than an appeal to Marx.
I've done some reading but when I cannot I just think about things on my own, maybe bounce ideas off a friend.
Word Vomit Contained inside
The view that I've come to currently is that violence (defined in this case as the obstruction or frustration of another's plans and ambitions) is a core universal tool which all living things employ. Language and cooperation were evolutionary evolved as a complement to violence (communication and cooperation allowed group violence which greatly improved survival odds). However, in cases where communication/cooperation with an outgroup breaks down, violence in some form will be fallen back on.
What's more, between two non-cooperative groups, if one group can obtain what they want through violence without losing more than they gain, they'll quite often choose that option as it is enticing.
Because of this natural progression, force-on-force is almost inevitable. To prevent being trodden upon by others, it is wise for a community to arm itself and train, thus greatly raising the cost of confrontations, hopefully beyond what others are willing to pay.
I would like to hear more from folks though, maybe just wise words on operation, maybe some sources to check out in my free time. Anything to better build my understanding is welcome.