GLM - agree with LB. I'd add that you must note that there is no correlation of light shot charge to low pressure. Chamber length is a red herring in picking loads for a gun of lower strength. You must know that the load is of low pressure. Lengthen the forcing cones to about 1 1/4" or so.

Low pressure is for the good of the metal and low recoil is for the good of the wood and the shooter.