Had my first experience with the Thompson Contender many years ago. I was visiting my daughter and her family and my son-in-law had some of his friends introduce me to that pistol. One of them made custom barrels and they started me out with the .30-30 and we ran up to, and through the .45-70. They had three frames and a box full of barrels.
Once, while firing the .35 Remington, I had a hangfire. I squeezed one off only to have the hammer remain cocked. I held it pointed down range for a minute, with my trigger finger alongside the frame, then brought the gun to the "pistol ready" position, gripping with two hands and held at forty-five degrees, prepatory to opening the action and ejecting the unfired ropund. At that point the pistol fired, whipping the front sight back into my right cheekbone. We were outdoors, and downrange was nothing for miles, so no danger. Other than my seeing stars for a minute or two. And putting a new slot in my cheek.
This frame had been used for load development and barrel testing and was pretty beat up from the abuse. Apparently some burrs held the hammer back, then let go.