The Federal Magnum Large Pistol Primer No. 155 has the fastest ignition of the Federal primers. They are so fast that they often ignite leadered bullets before the next round has left the chamber. Some dents are too small to explode them, which makes these primers ideal for hard-recoiling cartridges and magnum cartridges. Federal has combined the best in priming mix and cup technology to provide reliable ignition you can depend on to go bang no matter what. The Federal answer to the demand for a better primer, the Kleanbore Primer series is an outstanding large magnum pistol primer. With exclusive technology developed by Federal, the Kleanbore Primer cannot be beat.