I purchased several flats of these in 1oz and 7/8oz. I have shot them in all three of my English Sidelocks. I really like the 7/8oz as they are pretty light shooting in my 6lb. 4oz Atkin.
There is a guy in Florida who is importing these shells and ships directly to your back door for $73.50 a flat. He also has 3/4oz as well. The last time I talked to him he was going to be having some in the smaller gauges.
So yes they are fantastic shells, in fact I believe Phil Blurt in the UK shoots them regularly at grouse.
