The cannonball or round shot was the projectile most often used. Both direct and ricochet fire could be used to hit a target. Round shot was most effective when used against formed troops in column and was somewhat less effective against troops in line. Soldiers were frightened of long range artillery fire because their short-ranged muskets could not retaliate against the gunners. The British deployed their soldiers on reverse slopes when possible to avoid losses from artillery fire, but all other nations generally arrayed their soldiers in the open. However, when under a severe bombardment by 50 Austrian guns at the Battle of Aspern-Essling, the French Imperial Guard redeployed from a 3-deep line to a 1-deep line to minimize losses and keep the appearance of a solid front. At closer ranges, the gunners switched to canister, an anti-personnel weapon. When canister was fired, its load of musket balls flew toward the target while spreading out.