The penalty for use of a handgun in a crime of violence wasn't available.
Members of the victim's family, who attended both days of the trial, declined to comment following the 6:20 p.m. verdict.
The defendant's father, who also had been at the trial, returned to Baltimore earlier Tuesday prior to the jury's decision, according to Sacks.
Williams took the stand Tuesday as the only defense witness, testifying about the events that led to the May 19-20 fatal shooting at Franklin and Locust streets.
Echoing testimony from other witnesses to the shooting, Williams said it began over unwanted attention Artis had paid to Williams' 17-year-old sister earlier on May 19.
"She told me a guy had disrespected me and I told her we'd go back and see what happened," Williams said, testifying he already had a loaded gun with him.
Williams contended that Artis also had a gun that night and was the aggressor.
"I asked Earlene who did it and she pointed to a guy," Williams said. "I said nothing to him and he pulled out a gun."
Williams said he reached for Artis' gun with his left hand while pulling his own gun from his waistband with his right hand.
"He smacked my gun and it went off. Everybody started to run," Williams said.
Testimony Monday indicated Artis ran, but mortally wounded, he only got two blocks, where his body was found early May 20 at the rear of 60 East Ave.
Prosecutors Gina Cirincion and Bill Hayden called Williams' sister Earlene as a rebuttal witness to discount the defendant's claim that he was already carrying a weapon when he went to confront Artis.
While she denied telling Hagerstown City Police that her brother went back to his Cannon Avenue residence and armed himself that night, Hayden confronted her with her sworn statement to the contrary made in June.
That fact alone shows premeditation, Cirincion said in her closing arguments.
"This defendant tells you he came to the scene that night looking for an apology ... with a loaded gun in his waistband?" Cirincion said.
No guns were introduced into evidence at the trial.