My research is in a very limited area, but it wasn't rare for the 14th Iowa to hear "fix bayonets" in 1864:
They did that when taking Fort DeRussy in March. The rebels surrendered.
At Pleasant Hill, La., April 9, 1864, preparing for a rebel cavalry charge, "“We were ordered to fix bayonets, and those in the front line dropped to their knees with their guns on the ground, while the line behind stood with guns to shoulders ready to the press the bayonets home in the horses’ breasts as they charged.” (John Ritland of the 32nd Iowa wrote in 1922.) The dense was devastating to the cavalry, but I haven't seen a record of whether the muskets or bayonets did more damage. I'm assuming the muskets did. In the same battle, Confederate Major-General Walker had given orders to rely on the bayonet to save time and ammunition. Conferate Major-General Taylor wrote in his report of the battle that “these orders were well carried out as many ghastly wounds among the federals testify.”
At Bayou de Glaize May 18, Brigadier General Mower ordered Colonel Shaw's brigade to charge with bayonets, and Brigadier General A. J. Smith reported they did so "with terrible slaughter."
And at Harrisburg, Mississippi, July 15, from a letter to Davenport, Iowa, Morning Democrat editor signed "Veritos": "The 14th and 27th Iowa and the 114th Illinois were immediately ordered into line of battle, to fix bayonets and charge the enemy’s position, which they did at a double-quick, and to reach the enemy we had to ford three ponds of water, waist deep; but Iowa’s brave sons never falter, when heroic valor is required. We charged three rebel brigades and one battery, and drove them over a mile, killing and wounding a great number of them."