Dave, I shoot 2.5" low pressure RST shells in mine. Some Flues 20's have burst the frames shooting high pressure shells. I don't remember the chamber length in my Flues 20, but several of my light American 20ga guns do have the short chambers. RST or PolyWad vintager type shells kill birds just fine for me...Geo

I no longer reload, so others who do will provide some effective load data for low pressure.

Last edited by Geo. Newbern; 05/08/18 08:09 AM. Reason: added final sentence