I've got a Winchester Black Shadow 12 ga. 1300 with a rifled slug barrel. I was sighting it in a few weeks ago & the brand new BSA scope blew off on the 3rd shot - dovetail screws were too short. Took it back to the dealer that mounted it & he put on 3x longer screws. Shot last weekend, from a lead sled mind you, and could not get anything to group (100 yds) & definitely no consistency (talking 4"-12" groups here). Tried 3 brands of slugs: Horandy SST, Rem. Corelokts, & Lightfields - all 2.75". Barrel is clean. NEVER had this much trouble sighting in a shotgun.

Anyone had this kind of trouble? Could the BSA scope be bad? Wanted to use it in November, but not the way it's shooting! Any help would be greatly appreciated!