Of 421,000 new three-year volunteers entering the Union army in 1862, only 50,000 joined existing regiments. Professional soldiers criticized this practice as inefficient and wasteful. It kept regiments far below strength and prevented the leavening of raw recruits by seasoned veterans. In 1862 and 1863, many old regiments went into combat with only two or three hundred men while new regiments suffered unnecessary casualties because of inexperience.
