Fired the gun today.
I did manage a 4 shots sight set then made a 5 shots group at 65 yards (right for battue purpose).
For my first experience with the gun AND with a peep sight I'm pretty happy. That will be accurate enough for my needs.
Unfortunately I didn't bring the gun home. It had to be modified for hunting and hunter's ownership purpose (invisible and revesrible modification to make it a 2+1 capacity rifle).
That has been done but we realized you can't fire more than one round without clips: all the rounds are ejected with the first case. So the gunstmith has to find me some clips.