About 15 yrs ago, I ran a test of different actions,(single shots vs repeaters) to find if action stiffness made any difference. I used a Douglas 22 BR 1-12 twist barrel for the test barrel using all the same loads, same cases. I used 4 different actions: a long single shot, a long repeater, a short single shot, and a short repeater. The stocks were factory BVSS stocks,(no bedding, no mods).
I shot 5 -5 shot groups out of each specimen, over the course of 4 days, starting in the morning when conditions were ideal.
After I compiled the data, the difference between the best agg and the worst agg out of 4 was only .058". Yes that's 58 thousandths.....over 100 shots.
I soon figured out how stiff, "stiff enough" is. Oh, in case you're wondering.... the small agg came from the long action repeater.