I have a Redfield Revolution 2-7x33 scope on my 22 Hornet/20 gauge mounted in low rings. Yes it's a small opening to the hammer but it works ok. I'm a believer of the lower the scope the better. My rifle is on at 25 and 50 yards. The shotgun patterns center left right but 2/3 above the bullseye 1/3 below. Works for me. Bonus - Winchester slugs hit very close at 25 and 50 yards.
FWIW, I have shot better groups with Brenneke slugs in 20 and 16 smoothbores than with FED/REM/WIN Foster style rifled slugs. They are what I keep in the elastic carrier on the stock of my 24F in 223/20.
