In Puerto Rico, between two and five Dudley-Sims Dynamite guns were used. These guns manned by a portion of the 4th Ohio Volunteer Infantry and placed under the command of Capt. John D. Potter of Company F. During most of the regiment’s trip, the guns were apparently pulled by oxen, though this report indicates switching human transport when necessary. Below is Capt. Potter’s report.
"Guayama, Porto Rico, August 7, 1898.
Fourth Ohio Volunteer Infantry
SIR: In pursuance of verbal order just received, I have the honor to submit the following repot in regard to that part of the action of August 5 in which my command participated:
I had in my command 32 men armed with Krag-Jorgensen .30-caliber rifles and 22 men handling two Sims-Dudley dynamite guns, 2 ½-inch bore. I followed the Fourth Ohio Volunteer infantry from Arroyo and did not take any part to speak of in the action until the enemy had been driven from Guayama and taken up a position on the hills north of the town.
About 2 p.m. was ordered with one gun to the support of our line of skirmishers and took position about 100 yards in their rear and 200 yards east of the city waterworks. Five projectiles in all were fired at ranges about two-thirds of a mile. After the second shot toward the pass, the fire of the enemy from that quarter cased. Two more shots were fired for moral effect. One shell was fired for the same reason to our left, just to the south of the sugar mill.
One of the guns as temporarily out of order and had to be replaced by the other. The second gun caught on the second attempt to fire, but afterwards discharged the load without difficulty. After the fifth shot, was ordered back to the Plaza.
On examination, both guns were found to be in perfect order, the only catch having been that the heat and dust had clogged the breach a trifle. As soon as oil had been applied, they worked absolutely without flaw.
I wish to take this occasion to express my appreciation of the manner in which my men conducted themselves. No horses being obtainable, they dragged the guns weighing 1,050 pounds) by hand fully 2 miles, most of the way over very rough ground, and in addition they carried 12 rounds (260 pounds) of ammunition. They had very little chance to handle the gun previously, but did so without trouble.
I should also like to extend my thanks to Mr. J. D. Stockley of the Sims-Dudley Defense Company, who accompanied me and rendered very valuable assistance.
I have the honor to be, sir, your most obedient servant,
J. D. Potter
Captain, Fourth Ohio Volunteer Infantry."
Clerk of Joint Committee on Printing, The Abridgement of Message from the President of the United States to the Two Houses of Congress. Vol. 3 (Washington: Government Printing Office, 1899). 143-144.