Semi-autos might be frowned upon in game shooting circles but they are perfectly acceptable in a pigeon hide.
In fact they have a couple of advantages over conventional side-by-sides and O/Us.
The first is their ability to dampen recoil: prolonged exposure to recoil is very tiring and can affect accuracy on days when you might shoot a lot of cartridges.
Second advantage is that they can be reloaded with the barrels pointing safely skyward all the time which means there is little likelihood of the muzzle picking up dirt or getting snagged in the netting.
The only disadvantage is that spent cartridge cases will get ejected in all directions so make sure you carry out a thorough search and clean-up when the day is finished.