On January 20, 1864 Major Marshall, along with his fellow staff officers, watched Andries Rhoodie's demonstration of a new rifle for General Lee. He assisted in placing human cut-out targets in a firing range out to 500 yards. As he returned to the firing line, he began to jokingly refer to the cut-outs by the names of various Federal generals. His fellow staff officers joined in. After the demonstration, he helped collect the cut-outs.
For whatever reason, Marshall took an immediate dislike to Rhoodie. When Rhoodie claimed he could deliver 100,000 AK-47s, Marshall expressed skepticism. Lee asked what he would do if Rhoodie failed to deliver. He replied a good horsewhipping to teach him to not brag. Rhoodie, however, was willing to risk it.
A few days later, the first shipment of AK-47s arrived. General Lee instructed Marshall to draft a letter to Colonel Josiah Gorgas asking him the feasibility of manufacturing copies of the rifles. He also directed Marshall to send a rifle and a stock of cartridges to Colonel George W. Rains to see if he could duplicate the strange smokeless powder that the rifle used.