There is your problem, in my opinion, the tighter the sabot the tighter the group, in general. Too easy or not seated well enough or barrel to hot you will get "blow by", which causes inaccuracy.
Very good possibility of that.My Encore likes a very tight fitting sabot and is capable of1" groups or better.The SuperGlideswill not pattern at all, they are all over the place.The Hornady Low Drags make 3-4" inch groups in my gun. Never tried the Crush Ribs.