C.J, If your talking about the Super X BRI slugs (in the silver box), I have been using these for many years, even before Winchester bought out the original designer. Ballistic Research Industries, I believe was the name. They were originally designed as a long range police round, and had amazing accuracy and penetration on vehicles, but did not always knock a deer down right away. The first thing Winchester did after buying BRI out was to soften up the slugs by swedging them from soft lead instead of using the hard cast lead the originals used. These are now real killers. I think these are the best value out there for the money. I have killed deer from 14 feet to 125 yards with them. The 125 yard shot was an 8 point buck feeding and walking straight at me, I watched him come from 200 yards away, and as I was loosing light fast, I dropped to prone in the snow and let him have it. I had utmost confidence in these slugs, or I would not have done it. The buck dropped in his tracks. All the other deer I have shot with these slugs have either dropped on the spot or gone down within 20 yards.