Really hard to tell from the low res pic, but a ton of the black militia/JBGC types from 2020 were carrying AR pattern rifles in 22LR. You could tell by the extra small ejection ports and the weird looking extractors. My best guess was they all ran out to the gun/surplus store the day before the photo op, asked the guy behind the counter for their "cheapest assault rifle," and ended up walking out with .22's. They'd probably be better off carrying their lil' Glock 26's with drum mags and auto switches.
@DumbDude43 Semi auto shotguns are reliable if you run the right ammo/spring combination. The problem with shotguns is that there's a million different types of shells you can shoot through them and almost none of them have the same recoil pattern. Most semi auto shotguns are recoil operated. If your recoil spring is for 1oz slugs and you're firing birdshot, the gun won't cycle due to the lack of recoil energy. The only people that every ran into issues with it were riot control cops because they would run non-lethal and lethal rounds through the same firearm, and non-lethal shells have basically 0 recoil. This is where you get hybrids like the SPAS-12 where you can run it on semi auto with big boy loads and use the pump to cycle bean bags.