Back in the late 80s I was a student at the S&W Academy, revolver armorers' school. An instructor brought me a Glock pistol, knowing I had attended the Glock school, for assistance in dismantling the gun. A customer sent the gun to S&W, blaming their ammo for a catastrophic failure. He too tried to clean a heavily leaded barrel by firing a jacketed Hollowpoint through it. You're not supposed to fire lead bullets through a polygonal barrel as it can cause excess leading.
He paid the price.