A shotgun slug is a heavy lea projectile, usually with pre-cut rifling, often used for hunting large game. The first effective shotgun slug was introduced by Wilhelm Brenneke in 1898, and his design remains in use today. Most shotgun slugs are designed to be fired through a smoothbore barrel, which means that they must be self-stabilizing and capable of passing through a choked barrel. Much later shotguns were produced with rifled barrels, and slugs were designed to be fired from them with spin stabilisation. As these specialised "shotguns" were far more accurate than a smoothbore gun, they also usually featured greatly improved sights. Many of these slugs use saboted sub-caliber projectiles, resulting in greatly improved external ballistics performance.