This Parker 20 was made in 1900 and as a kid, I shot field loads and SuperX 6 s in it with no problems.
A few years ago, a gun maker friend took it and "freshed" it up a bit as well as removing some barrel dings. When he returned it to me, even though he and another well known double man found no specific faults, he recommended that I shoot RST or other light loads and to not shoot express or heavy loads. I have followed his advice and still hunt with it a few times per year.
Most of my bird shooting is now done with newer Parkers.
Moral - have a qualified gunsmith examine your gun and pay close attention to his advice.
Good hunting!
