In the First Battle of Kernstown on 23 March 1862, the Union troops temporarily under the command of Nathan Kimball included 4th U.S. Artillery, Battery E (Clark's) armed with six 10-pounder Parrott rifles. At the Battle of Antietam on 17 September 1862, the Union Army of the Potomac counted 57 10-pounder Parrott rifles while the Confederate Army of Northern Virginia had at least 43 available. Union 10-pounder Parrott rifles were almost all massed in four or six gun batteries. Meanwhile, the Confederates distributed theirs by ones, twos, or threes in mixed batteries. The six-gun Union batteries included Battery B, 1st New York Light Artillery (Pettit's), Battery A, 1st Rhode Island Light Artillery (Tompkins's), Battery A, 1st New Jersey Light Artillery (Hexamer's), and Battery D, 1st Pennsylvania Light Artillery (Durell's). McCarthy's Richmond Virginia battery consisted of two 10-pounder Parrott rifles and two 6-pounder field guns.