[Jewbacca]

The recoil would destroy the average flir after a couple of shots.

[Jewbacca]

Sorry, just realized I already gave a more-detailed answer!

[MrEdd]

Recoil can be eliminated or mitigated depending on the design.
I would not imagine (for example) that the recoil on my old HK91 would have been terribly damaging.

For an air gun I rather envision a heavier than needed receiver milled out of a block of steel with a large gas cylinder attached. Since my goal is to have it sit in one place and aim it with servo motors it probably would be wasted effort to make a slim design suitable for hand carry.

Being heavy and attached to a stationary post out in a field where the pigs are would pretty much eliminate recoil problems.