Actually, pulling a load was necessary on a regular basis for a number of reasons;
(1) When returning from guard duty with arms loaded in the field whether near to the enemy or not, arms were loaded and ready to fire.
(2) When expecting to go into action, arms were made ready. If the troops were not sent in or for some other reason did not have to discharge their weapons they returned with loaded firearms.
(3) in case of a misfire and that happened occasionally after firing on a humid or very dry day.
(4) Troops spent the night lying on their arms during inclement or severely damp weather expecting action at any time. This happened more often than you think, one example is the Stonewall Brigade the night before their destruction at the Bloody Angle. The Union attack was expected all night and when the Federals hit just before dawn, the Southern troops attempted to fire to repulse the attack and a large percentage of the muskets failed to fire. A volley of popping percussion caps and only a few actual rounds discharging brought a cheer from the yanks as they charged the veteran rebels who could only defend themselves with a bayonets, clubbed muskets and a few functioning muskets. In the days of flint guns, this problem was even more severe.
When any of the above happened, the ball had to be pulled and, when possible, the powder saved. Why? Army frugality, especially in peace time. Ammunition was expensive and often hard to get. Occasionally, in the field during heavy operations, there would be facilities set up by the regimental armorers for remaking ammunition, especially if a great deal had been expended and a source of replacement ammunition was not close by. If not remade in the field, components were sent back to contractors to be remade.
