What if I don't happen to have random gun parts around the house? Can this still be done?
Not very easily without the right equipment and metal working skills.
I'm building two AKs at the moment. Both are from parts kits I bought (just a complete bunch of parts minus the receiver). The receiver on the other hand, was purchased as a 'flat', and therefore not a firearm. Once I put those flats in a jig (got a metal break or bending jig?) and bent them, they became 'firearm receivers'. So yeah, as long as one can obtain 'parts', one can make the receiver out of a flat... or a shovel.
Then comes the de-milling (grinding and removing of old rivets if remains of old cut up receiver are still attached to trunions), pressing the pin and barrel out (do you have a 12 ton press?), filing of new receiver for correct fit of trunions, tacking in of rails (clamp type spot welder), riveting tool, pressing barrel back in, more riveting, headspace check (requires headspace gauges), heat treating (torch), and re-finishing (paint, heat treat paint, or parkering (special chemicals and process, etc)
Or, get an AR parts kit with a complete upper, find a stripped lower receiver (the part that requires ffl, paperwork, etc), and put it together with a small punch, hammer, and screw driver in a half hour or less.
Because currently I don't have a gun, but if the country went sideways, it'd be nice to know that I could construct one out of a shovel.
The panic buy prices of last year are over..... for now (can't speak for a year from now). ARs can be had for $400-500 if home built, $600+ at stores. I would just try to save up the green and buy one now. Ammo is also back down to a somewhat tolerable price. 1000 rounds of 5.56 costs $400-450 if bought in bulk (was $900 earlier this year). 10,20,30 rnd mags can all be found under $10.
Yep, find the right places to buy and for less than $1000 you'll have a nice rifle and a decent amount of ammo to survive any end of the world/political chaos uprising/zombie onslaught that may arise, with enough for some training before-hand.
The AR platform is the 'lego set' of firearms. Mail order a 9mm upper, pull two takedown pins, swap uppers, done. You can get a drop-in 22lr conversion for cheap practice too.
I assume you could go the distance and turn numerous other household parts into gun accessories. The shovel was really more of a example than anything.
Certainly an interesting way to come up with a receiver. I saw another series of pictures by the same guy where he made a single shot shotgun look like an RPG launcher.