For the Napoleon: Total War technology, see Rifled Cannons (Napoleon: Total War).
Rifled Cannons are a Technology in Empire: Total War.
Description[]
Rifling a barrel increases the accuracy of a weapon, and this principle can be applied to large cannons as well as small arms.
Ordinary naval cannons are smoothbore weapons, meaning that the barrel is a simple tube to contain the explosion. The limitations of casting mean that cannons are quite crude and windage, the gap between the barrel and shot, is always a problem. A shot often "rattles" down the barrel when fired, making it inherently inaccurate. The loss of accuracy with a smoothbore makes its maximum range of academic interest only, simply because it becomes a matter of luck rather than judgement to hit anything far away!
A rifled cannon solves these problems. By using machines to bore out the barrel from a blank casting, one inaccuracy is removed. Another machine cuts a helical pattern of grooves into the barrel wall. This imparts a spin to any shot as it travels down the barrel, and a spinning projectile flies true. This makes the effective range of a rifled cannon shot much greater than one from a smoothbore, although the maximum range for both is similar.
Historically, rifled cannons used manufacturing techniques developed for making accurate steam pistons and cylinders.
General Information[]
Rifling makes cannons significantly more accurate, particularly at longer ranges. However, despite in-game descriptions, it does not increase the maximum range for any ship.