On January 27, 1863, the battery was transferred to Grand Gulf, Mississippi, joining the defenses on the Big Black River. While stationed at Grand Gulf, the battery participated in several minor engagements with Union gunboats, although some of the artillerymen reported boredom. In mid-March, the battery guarded a point known as Winkler's Bluff on the Big Black River, with orders to allow no boats to pass the point. On April 29, Union Navy vessels commanded by Admiral David Dixon Porter bombarded the Confederate position at Grand Gulf, resulting in the Battle of Grand Gulf, although Landis's Battery was not part of the Confederate front line. One fort held out, so Grant landed 24,000 men downriver at Bruinsburg. These men soon moved east from the river, leading Brigadier General John S. Bowen, the Confederate commander at Grand Gulf, to send a blocking force to Port Gibson in an attempt to stop Grant's incursion. During the morning of May 1, Landis's Battery's two howitzers and their crews were sent to join the blocking force. During the Battle of Port Gibson, the battery fired at men of Major General John McClernand's Union corps and engaged in an artillery duel with the 8th Michigan Light Artillery; the unit suffered three casualties during the fighting and did not disengage until the late afternoon. At one point in the battle, the battery was also subjected to Union sharpshooter fire, before dispersing their attackers with canister. Despite holding initially, Union pressure eventually drove in Bowen's right, causing the Confederates to retreat before Grant outflanked them. After Port Gibson, the Confederates were forced to abandon their position at Grand Gulf on May 3; Landis's Battery again served as part of a rear guard.