thanks tac, that certainly gives me something to start researching, I've asked on fullbore but mostly people have just posted about why i cant shoot nitro.
basically the range is bedfrordshire county range, so its a smallbore range. that we were allowed to start shooting black powder at, and pistol calibre rifles. as in my post above, we initially asked if shotguns could also be shot there, but it was a no, the club then managed to get them agree to us being able to shoot black powder slug 12g as it isn't all that different from someone using something in a large calibre, but allowing people to use shotguns if they had them. i would assume the 1550 fps limit hits nitro shotgun shells? or because of the spread of shot with the design of backstop maybe? or maybe just because they didn't want shot spread across the 100yrds of grass which might be a problem with the mower?? i wasn't involved in the discussion so i just dont know
it is a PITA, but I'm not sure where i can go to shoot a sec1 shotgun and not cost the earth, as i was told i wouldnt be able to take it where i'm starting to shoot clays.