RWS musket caps are versatile and may be used with any kind of powder, including Pyrodex Powder, and any current muzzleloading firearms. These caps have a ribbed “U” shape, and the Sinoxid priming component within is non-corrosive, hot, sensitive, and constant. It does not include any mercuric. They have a long shelf life, don’t attract moisture, and burn evenly and quickly. Furthermore, they don’t absorb moisture. RWS caps are compatible with all side locks and in-line applications.