13 little-known facts about Joseph Smith
A near-death experience
"Apostate William Law attempted to kill Joseph and fired a pistol at him six times at close range. It misfired six times, and he then pointed it at a post and all six shots discharged properly."
Charles H. Stoddard, "Remembering Joseph,"
Trying to find out more, I found this link which repeats the story fairly differently.
As they approached their destination, Mr. Law came staggering out of the house shouting out what he intended to do. The Prophet said kindly and unafraid, “You sent for me, Mr. Law?” To which Mr. Law replied with oath that now he was going to do the whole world a favor by disposing of the Prophet with one shot. Calmly, the Prophet unbuttoned his shirt and bared his chest, and then said, “I’m ready now, Mr. Law.” Charles said at this point he nearly fainted. Sick fear strangled him until he was speechless and paralyzed, unable to move a muscle. Mr. Law paced a few steps, turned, aimed, and pressed the trigger. There was complete silence. Then the air rang with profanity and Mr. Law turned on Charles, accusing him of fixing the gun so it would not go off and threatened to kill even Charles—my innocent, frightened, but faithful son. The Prophet, to divert Mr. Law’s blame of Charles, suggested that a can be placed on a fence post for Mr. Law to take a practice shot. Relieved, Charles ran for a can and laid it on its side on a post. Mr. Law paced back, took aim, and fired. His one shot streaked through the exact center of the can. Even Mr. Law was quiet as if stunned. The Prophet buttoned up his shirt, gave Charles a meaningful look, and then said, “If you are finished with me now, Mr. Law, I have other things needing to be done.” (As quoted by Robert H. Daines at BYU-Idaho Devotional, 28 May 2002)
And also claims:
Joseph Smith had asked Charles Stoddard, age 14, to serve as a house boy for William Law. William Law was one of the Prophet’s enemies, and felt by many to have led the charge on Carthage.
I'm not an expert, but I assume they are talking about the William Law. As the Nauvoo Expositor William Law.