the only essential firearm is the one you have when you need it.
unfortunately, do to a boating accident, i know longer have any firearms... or a boat.
I too, as a matter of fact loss all my firearms to a tragic boating accident. If only I could have been smart enough to try and triangulate just where I was in the body of water, when the boat sunk. But it was a very windy nite, and the fog had just come in. Lost all of my weapons. What a shame. I've still not recovered from that loss, so many years ago.
To one and all, do be careful, and avoid hot lead, especially @ sub-sonic speeds. I hear it can be very painful.