I had one of those before I upgraded to an Encore. Fantastic shooter. It loved 100 grn of loose 777 powder pushing a 250grn Hornady SST with the low-drag sabot and a 777 primer. I could get 3-shot groups that were almost cloverleafed.
The choice of a regular 209 shotgun primer or a specific ML 209 sized primer is dependent on the powder you are using. If you are using Pyrodex or 777, then use a primer made for a ML only. They both need the hotter ignition. If you are using Blackhorn 209, then I believe you need to use a regular 209 primer.