I have real world experience.
.44 mag. Integral suppressor. Bolt action. Shooting 300 gr XTP .44 special. Super quiet. Ok for a blind Super heavy.
300 blackout. 9 inch Thunderbeast Ultra. Lehigh 194 bullets. Super, super quiet. Single shot break action, 16 in barrel. About 5 lbs.
For those who say these are "questionable" in lethality, I have killed about 10 deer with them. All but one were pass thru. They all fell within sight. The Lehighs are purposely lethal bullet designs for subsonics.
If you order a can right now, there is a chance you will get it in time for next year.
Air rifles capable of killing a deer are loud. Orders of magnitude louder than these rifles. Unless you suppress them too.