I use the Nitro card a lot, mostly for protection of the bottom of the bullet from the heat generated by T7 or BH. They really work well for me when shooting the 460 BullShop. One thing that I found that I need to do is wipe the base of the bullet off so the wad does not adhere to the base of the bullet. I have recovered spent wads and the land markings on the edges a very visible. I really think the in combination with the heat, pressure build, and the obturation of the bullet the wads do seal very well.