I've been following this Thread without comment. The article in Dr. Wankers' link by Michael Yardley has good advice. I also have Yardley's book. "Gunfitting", and one thing stands out.
I can't recall anywhere Yardley suggests shooting a bird or clay target gun off sandbags. To get a good representation of point of impact from a pattern board, it seems apparent that shots at the pattern board should be taken using the same mounting and shooting style one would normally use on birds or clay targets. Save the sandbag rest for the slug gun and rifles.
