I have been breaking in an HW97K mostly in the house at 10 yards, with my target sheet taped to a USPS medium flat rate box full of rubber mulch. I can shoot at least 10 shots with the 8.4s in roughly the same half-inch before the pellets start chewing their way toward the back of the box. But with the Baracuda Math 10.65s, I am getting full penetration in as little as four shots. Instructive!