20 gauge....
If the gun is merely broken, I should have a few extra rounds around, which I can take apart and should be able to create a fire, as long as I'm careful and do not blow up myself...
An auto or pump will supply me with a spring or two, and I can make snares out of that. The barrel, removed, will make a beautiful club/throwing stick, as well as a rather functional straw for a solar still or a water pit dug in a low lying area.
Most metal parts will be hardened too much to bend effectively, but they could be sharpened/carved to make lures and hooks for fishing. Pieces from the action of the right shape could be manufactured into a blade of some sort.
The barrel very well may be of high enough carbon to spark on a suitable hard rock, and could be used for firemaking if it does.
If it has a wood stock it should be impregnated with enough oil or other flammable stuff to approach pitch wood for fire tinder. Synthetic stocks may or may not do well for fire making.
A full length stock would make for a nice club, and shorter ones could function well as digging implements once sharpened a bit.
As for other stuff, what kind of gun is it? Auto, pump, over/under, side-by-side, falling block, single barrel break open? Wood stock? Scope? Was I carrying large shot? slugs? small shot? do I have rounds left over?
Stryver