That saw idea was pretty crafty but way too short for functionality. Since we are on bladeforums, that knife looks hideous and toyish. Also since we are talking, "run out of the house grab one thing" type of survival I would want a lot more range.....something more like a scoped rifle with sidearm.
Scopes and survival make me twitch. You want a lot of beef and are going to have a lot of expense if you are going to go that route. You also lose 90% of your hunting capability. Yes, on deer at 250 yards is great and if you can process it it should keep you going for a while. But you lose out on bunny, most smaller furbearers (gopher, porcupine, hedgehog, squirrel, racoon, etc.) and you lose out on fowl entirely- except set shots on turkey.
A lot more range than what? With modern slugs you are looking at a solid 150 yards with the possibility of making a 200 yard shot with a 12ga if you are prepared and have practiced it. The main differences here are - 20ga gives you a bit better ballistics at the 100-150 yard range, but 12ga will pack more punch at those ranges. Even with 20ga, we're looking at well over 800 foot pounds at 100 yards with a buckhammer/brennekke style slug load.
Incidentally- brennekke now makes a 28ga slug load, looks suitable for up to mulies with good shot placement at 35-50 yards. Doesn't make the 28ga a lot better for me, but I could see it working out for some.
.410- you go down to 50 yards tops. But this becomes environmental. Back in Northern AZ I would have felt okay with it. Out here in the basin, I'm more likely to get the 100 yard shot opportunity.
If you are
absolutely relying on > 150 yard shots, and will hunt
nothing in the small game category, break out the .308, 3.75, .30-06, or similar and a big scope and go to town. I'm going to be a lot more comfortable with a shotgun.
Yes, you said sidearm. Again- shooting quail or tree rat with a .22 pistol (use a .38 and there's no point) is possible, but not that easy. I'll happily give myself a max range of about 35 yards, braced, slow shot, with my .22 revolver. but I'll get a lot more out of the shotgun in that type of hunting, by far.