For better than two decades, I used an AR-7 as my "Jeep Gun". Never needed it for anything other than plinking and bunny killing.
Then there was an incident when that little .22 just seemed so small and underpowered. I undertook to create the "Perfect Jeep Gun". Casting about for something that was still light and portable, yet more able to handle two legged critters, I found it in my gun safe.
There it was, my first shotgun, a Mossberg .410 model 500. By shotening the barrel, installing a "youth" buttstock, and adapting the stock bolt for easy removal and replacement, I was able to break it down, rapidly, into a package about 20" long. The buttstock cap is not secured with industial strength velcro for quick attatchment and removal.
It only takes about 30 seconds to assemble. And once assembled, the .410 is capable, with slugs, of dealing with the above mentioned critters much better than the .22 lr.
Now, you ask, what about the AR-7. Well, mine is one of the good ones, reliable, and with a scope attached fairly accurate. It now lives in our emergency get out of Dodge bag that contains important papers and such.
Here are a couple of images with the AR-7 for comparison.
So, as an addition to you BOB, not a bad idea. But it is a "last ditch" firearm in that department. And since they are light weight, and take up little room, why not?