One time with a .50 cal. muzzleloader. One morning I was in the stand watching the area near a persimmon tree when a doe walked right in under my stand. I thought to myself, alright some fresh meat. I eased the safety off on the Omega, took aim and pulled the trigger. The gun did not fire and the trigger felt like the safety was still on. I thought I was a dummy and still had the safety on. I looked again and the safety was off, showing the red dot to indicate that it was ready to fire. I worked the safety back and forth and tried again. By this time the doe noticed all of my movement and started running off. Being mad I aimed at her rump and said fire you bastard muzzleloader. Nothing happened and the doe ran away. I was mad enough to throw the muzzleloader at her. Being disgusted I climbed down out of the stand and walked to deer camp. I got the tools out and thought I would take the muzzleloader apart to see what the problem was. I worked with the firing parts and thought I saw some type of material fall out from the trigger area. I then worked the firing system and it started working just fine. At that point I realized that the day before I helped drag a deer out. I remembered having the gun strapped on my shoulder and the gun (without primer on breech plug) got hung up in a small bush. I think a small limb end got caught in behind the trigger and broke off. When I was on the stand and tried to shoot the deer that small piece would not let the trigger go all the way back. I did learn a lesson on that day. I am just glad that I was not trying to take ol big boy.
Other than that malfunction (knock on wood) I have never had any other miss fires while trying to take a deer. However my brother in-law had his muzzleloader to misfire one day he was trying to shoot a big 10 point. He discovered that his pyrodex pellets were bad and he was mad that day.