Captain Richard Waterman of Battery C, 1st Rhode Island Light Artillery believed that the 10-pounder Parrott rifle was more accurate than the 3-inch Ordnance rifle at 900–1,500 yd (823–1,372 m) range.
Union General Quincy Adams Gillmore liked the Parrott rifles, noting that untrained artillery crews could easily learn how to operate them.
Confederate officer Edward Porter Alexander wanted to get rid of his 10-pounder Parrott rifles and replace them with M1841 24-pounder howitzers.
One artillery officer reported that the Parrott percussion shells performed very well with only two shells failing to explode out of about 30.
The tendency of the Parrott rifles to burst without warning made them unpopular with their gun crews.
Union Private Augustus Buell of 4th U.S. Artillery, Battery B wrote, "If anything could justify desertion by a cannoneer, it would be assignment to a Parrott battery".

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.

At the Second Battle of Corinth on 3–4 October 1862, Battery H, 1st Missouri Light Artillery was armed with a mix of 10-pounder Parrott rifles and 24-pounder howitzers.
In 1862 alone, the US government ordered 270,699 Parrott projectiles.
This included ammunition for Parrott rifles other than the 10-pounder.
On 2 July 1863 during the Battle of Gettysburg, the six 10-pounder Parrott rifles of the 5th U.S. Artillery, Battery D commanded by Captain Charles E. Hazlett took position on Little Round Top.
When General Gouverneur K. Warren pointed out that the guns would not be able to fire on their attackers, Hazlett replied, "The sound of my guns will be encouraging to our troops."
In mid-war, the Army of the Potomac began replacing the 10-pounder Parrott with the 3-inch Ordnance rifle.
By May 1864, only five of the 49 batteries in the Army of the Potomac were armed with 10-pounder Parrotts.
The Parrott rifles were not used again after the end of the war.
Captain Richard Waterman of Battery C, 1st Rhode Island Light Artillery believed that the 10-pounder Parrott rifle was more accurate than the 3-inch Ordnance rifle at 900–1,500 yd (823–1,372 m) range. Union General Quincy Adams Gillmore liked the Parrott rifles, noting that untrained artillery crews could easily learn how to operate them. Confederate officer Edward Porter Alexander wanted to get rid of his 10-pounder Parrott rifles and replace them with M1841 24-pounder howitzers. One artillery officer reported that the Parrott percussion shells performed very well with only two shells failing to explode out of about 30. The tendency of the Parrott rifles to burst without warning made them unpopular with their gun crews. Union Private Augustus Buell of 4th U.S. Artillery, Battery B wrote, "If anything could justify desertion by a cannoneer, it would be assignment to a Parrott battery".
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. 
At the Second Battle of Corinth on 3–4 October 1862, Battery H, 1st Missouri Light Artillery was armed with a mix of 10-pounder Parrott rifles and 24-pounder howitzers. In 1862 alone, the US government ordered 270,699 Parrott projectiles. This included ammunition for Parrott rifles other than the 10-pounder. On 2 July 1863 during the Battle of Gettysburg, the six 10-pounder Parrott rifles of the 5th U.S. Artillery, Battery D commanded by Captain Charles E. Hazlett took position on Little Round Top. When General Gouverneur K. Warren pointed out that the guns would not be able to fire on their attackers, Hazlett replied, "The sound of my guns will be encouraging to our troops." In mid-war, the Army of the Potomac began replacing the 10-pounder Parrott with the 3-inch Ordnance rifle. By May 1864, only five of the 49 batteries in the Army of the Potomac were armed with 10-pounder Parrotts. The Parrott rifles were not used again after the end of the war.
10-pounder Parrott rifle