An SKS with 16" barrel and open sights would find a good home in your tool tub. (My 20" SKS measures 1020 mm.) Any rifle with cheap scope and mounts isn't going to like smashing into your waratah lifter, fencing spade, pliers etc.
Used to carry a Defender or SKS in the Hilux but very often their limited range meant that I was missing opportunities. These days I just decide on the most suitable firearm for area I'm working, and put it in a hard case behind the seat.
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