Fishing sinker fish being pursued, the environment, the current and personal preference. Pyramid sinkers are shaped like a pyramid and are used when it is desirable to anchor on the bottom of water bodies. They are attached to the terminal end of fishing line by loops of brass. Barrel or egg sinkers are rounded and often bead-like with a narrow hole through which fishing line is threaded. These sinkers are desirable on rock or debris covered substrates. Split-shot sinkers are small and round with a split cutting halfway through the sinker. The split can be placed on a piece of fishing line
Hollow-base bullet developing a hollow-base bullet was to improve utility of muzzleloaded blackpowder rifles. Hollow-base bullet A hollow-base bullet is an expanding bullet that has a pit or hollowed out shape in its base often intended to cause the bullet to expand upon firing a cartridge in order to expand the base against the barrel grooves and obturate the bullet more as it travels through the barrel. It is also used for improved aerodynamic stability and accuracy as hollow-base bullets are usually front-weighted which enhances their aerodynamic stability. Two men have been credited of the invention of the hollow-base bullet: Captain Claude-Étienne