Whilst a member of Cobham rifle and pistol club, we had totally wind free ranges, with butts at 25, 50 and 100 yds. Sub 1" groups at 100yds were readily achievable, even with sub 12ft llb .177 airguns
We used to put spent .410 cartridges, end on, on the 100yd rail-used to knock them off pretty much 10 out of 10 shots (Logun Mk2 pro with an inline mag-set up for Accupels).

I remember the warm, Summer afternoon when John Budd and I were happily knocking a 2" wooden ball threaded onto a string, tied to the 100yd rail, (whilst it was swinging) Bob Ruggles from Lea Valley had paid us a royal visit-I don't think he could believe what he was seeing.

Happy Days