Originally Posted By: salv
Pistol caliber lever action. Rossi R92 or Marlin 1894 in .357/.38 special. No recoil, low noise, relatively powerful, durable and reliable, lots of options for ammo, and better yet, since it is a tubular magazine, it is exempt from the NY Safe Act 7 round loading limits.
The "ammo shortage" in my area is normally for the military calibers [9mmPara, 45ACP, 5.56, Russian calibers]. I second Salv's suggestion of a lever action .357/.38spl. carbine up to 18" barrel. I have always been able to buy either .357 or .38 spl.
As much as it breaks my heart, I'd steer you away from a Marlin (which is USA made) because of a known design defect called the Marlin jam. It isn't expensive to fix if you can do your own work. My local gunsmith fit a part that I made into the shell elevator and when I get some decent weather I'll take the gun out for a torture test of the repair. The smith's bill was still $100. The Henry is also USA made, but is heavy, expensive, and only loads by taking the gun out of the fight.
The Rossi Winchester clones are good guns for the money and have no known mechanical issues. The Winchester action, designed by John Browning, is not user friendly to dismantle and clean. All of this can be YouTubed to see what I mean.
The carbine .357 will almost DOUBLE the muzzle energy of the same ammo out of a revolver. At home defense ranges, I am sure it will be a one-shot stop IF you practice enough!! A miss by an elephant gun is worthless versus a hit with a .22
Practicing with ammo you can buy is much better (and not THAT much more) than limiting your practice if you can't buy sufficient ammo. I also think it's better to practice with the gun you'd use if it came to that. Familiarity with the controls and the lever so that you don't have to think when it's the hardest thing to do.