Who invented the “Foster” shotgun slug?
A. The Foster slug was invented by a Karl Foster around 1931. It is characterized its deep hollow base design which places the center of mass very near the tip of the slug, much like a badminton shuttlecock. If the slug begins to tumble in flight, body drag will tend to push the slug back into straight flight. This gives the Foster slug stability and allows for accurate shooting out to ranges of about 75 to 100 yd, depending on the barrel Most Foster slugs also have “rifling” that consists of thin fins pressed into the outside of the slug. Contrary to popular belief, these fins do not impart any spin to the slug as it travels through the air, because the slug’s passage through the air pushes a shockwave ahead of it that creates a vacuum on the side of the slug, where the fins are located. The actual purpose of the fins is to allow the slug to safely be swaged down when fired through a choke, although accuracy will suffer when such a slug is fired through tighter chokes. While designed
