Sure, a .22 kit will send an Aguila 62 gr down range and cycle the action....but I want to be the guy that made the subsonic load that cycles a standard AR. As meaningless as it may be to most people, it is a puzzle that hasn't been solved yet and I love puzzles like that.
It has not been solved yet because it is not probable. Anything is possible, so I am not going to say it is impossible. Getting an AR to cycle with subsonic is like getting a 350 horse power V8 sport car to get 50 miles per gallon.
You have a gun that is designed to some relatively strict tolerances to reliably fire a 60 or so grain 5.56mm projectile at 3200 feet per second. You want to use that same gun to fire a 5.56mm projectile at 1000 feet per second. Just not going to happen. The only possible way to make it work would be to add a lot of weight to the projectile. You can not increase the diameter and you can only go so far with the length. cant really increase the weight of lead. Maybe you could use some uranium or osmium.
5.56 60 grain at 3200 fps has 1364 foot pounds of energy with 27 pounds of momentum. Reducing the velocity to 1000 foot per second you would need a 200 grain projectile to get that much momentum and have about 445 foot pounds of energy.
If you can figure it out, more power to you. You will definitely be a rich man.