A firearms analyst also testified that Ward's 12-day-old purchased 40-caliber semi-automatic handgun would not fire from just a bump to it.
Ward's trial on a depraved-heart murder indictment resumes Monday at the Lee County Justice Center. It started Tuesday with Judge James L. Roberts Jr. presiding.
McCoy, a 20-year-old Itawamba Community College soccer player, died at Ward's home on the night of April 15, 2010.
The 25-year-old Saltillo man and his attorney, Victor Fleitas of Tupelo, insist her death was a tragic accident, not a murder.
The gunpowder residue expert, Alisha Smith of Jackson, said she found traces of gunpowder on McCoy's and Ward's hands but said she had no way of determining if one had a higher concentration than the other.
Police said Ward told them McCoy was playing around and the gun went off as she passed it to him.
Earlier in the day, Megan Riley of Lee County E-911 verified the accuracy of recordings the emergency agency made of frantic phone calls from Ward and his father just after McCoy was shot at their home.
Other witnesses included Scruggs' Farm Supply employee Corey Campbell, who sold Ward the gun on April 3, 2010; Adam Foresman, who worked with Ward at Computer Universe and whom Ward showed a tactical light he'd purchased for his new gun; and Joseph Giroux, then a part-time Lee County deputy who discouraged Ward from target practice near his house on April 14, 2010.
While Fleitas' questions were tough on Smith - to press her to admit that little difference existed between "positive" and "indicative" traces of gunpowder - he was especially hard on Ginny Lloyd, a 30-year-old Tupelo woman who claimed she witnessed Ward acting abusively to McCoy at a Christmas party in 2009.
"You hate my client," Fleitas said to her. She denied it. She also denied she was sexually attracted to McCoy and jealous of Ward.
The defense tried to prevent Lloyd from taking the stand, saying her story was highly damaging to Ward, but prosecutor Richard Bowen insisted that to prove their case, it was crucial to prove allegations of Ward's reckless behavior toward McCoy. Prosecutors also are District Attorney Trent Kelly and assistant Josh Wise.