Upon attempting to sight my 935 Cant. Slug barrel in, I found that there must be a major problem with it. I tried Winchester BRI, Federal Premium Hydroshok, and Federal Premum Barnes expanders. None would group and I started noticing the holes in the paper were keyholed, buddy shot same slugs as I was into the same target and no keyhole!!! Ended up getting some remington Buckhammers and sighted them in and they flew fine(as expected) but I just coulnt believe that sabots were tumbling out of a new rifled barrel!!!! Any one ever heard of a problem like this???