How insane is it that you could own a deadly machine like an AR-15 and not need to register it?

[Kaleva]

220. I don't think there are any hunters in your family

If there were, they'd know the AR-15 platform is capable of firing a wide variety of ammo.

Here is a partial list:

"AR-15 cartridges

Rimfire cartridges
.17 HMR[1]
.17 Mach 2
.17 Winchester Super Magnum[1]
.22 Long Rifle[2]
.22 Winchester Magnum Rimfire[1]

Centerfire cartridges imperial measurement
.17 Mach IV
.17 Remington Fireball
.17 Remington[1]
.17-223[3]
.20 Practical[4]
.20 GPC (wildcat)
.22 GPC (wildcat)
22 Grendel (wildcat) aka 224 Grendel
.22 Nosler
.22 PPC
.204 Ruger[1]
.222 Remington
.223 Remington - Original AR-15 cartridge: .223 cartridges may function in a 5.56×45mm rifle, however 5.56×45mm cartridges may produce excessive pressure in a .223 Rem rifle. On the other hand, a .223 Wylde chamber is used on .223 Rem rifle barrels to allow them to safely fire either .223 Remington or 5.56×45mm NATO ammunition.[5]
.223 Winchester Super Short Magnum[5]
.224 Kritzeck (wildcat of a .223 Remington with shortened neck)[6]
.224 Valkyrie
.24 GPC
.243 LBC[3]
.243 Winchester Super Short Magnum[5]
.25 Winchester Super Short Magnum[5]
.25-45 Sharps
.257 Ocelot (wildcat)
.25 GPC (wildcat)
.26 GPC (wildcat)
.27 GPC (wildcat)
.277 Wolverine (semi-wildcat)
.277 MSR (Dasher Wildcat)
.28 GPC (wildcat)
.30 American[7]
.30 Carbine[1]
.30 GPC (wildcat)
.30 Remington AR[8]
.30 Sabertooth (wildcat)
.300 OSSM[5]
.300 AAC Blackout (7.62×35mm)[8]
.300 Whisper[8]
.300 HAM'R - Wilson Combat[9]
.338 SOCOM (wildcat)[10]
.338 Spectre (wildcat)
.350 Legend[11]
.357 Automag (wildcat)[12]
.358 SOCOM (wildcat)[13]
.358 Yeti (wildcat)[14]
.375 Stalker (wildcat)
.375 SOCOM
.400 AR (wildcat)
.40 S&W[15]
.44 Automag (wildcat)[16]
.44 Remington Magnum (wildcat)[17]
.44 SOCOM (wildcat)[18]
.440 Corbon Magnum (wildcat)[19]
.45 ACP[20]
.450 Bushmaster[1]
.458 SOCOM[21]
.475 SOCOM (wildcat)[22]
.499 LWRC
.50 Action Express
.50 Beowulf[23]
.50 SOCOM (wildcat)[24]"

https://en.wikipedia.org/wiki/List_of_AR_platform_cartridges

One can even purchase AR15 style shotguns which could be used for bird hunting.

Below is a link to a site where one can purchase such:

https://atlanticfirearms.com/ar15-shotguns