Like Eterry, I suspect that its a failure to properly clean the oils out of the back end of the barrels that leads so many of the guns to misfire when taken inside and then back out several times to shoot, finally. But, I have seen guns in other people's hands that swear they cleaned and dried the flash channel, that still misfired when they left the gun loaded for several days, taking it in and out of the house. I have also heard Hang-fires occur with other people's guns.
At the time I began hunting with MLers, state law required the guns be UNLOADED- meaning no powder and ball down the barrel for transporting them in any kind of vehicle- and that included any vehicle with a motor. So, I had no choice but to fire off the load at the end of the day. I also had no choice about loading the gun at home- it was illegal, also. So, I loaded my gun at the field.
Transporting the gun in my car from home to field occasionally left me a wet bore, from condensation. It all depended on how cold, and wet it was outside on the morning( night) when I left the house.
So, I began following these old rules. I cleaned and dried my barrel again at the field in the light of the dome light in my car or truck, before loading the powder charge. I liberally greased a cloth patch, and ran that and the ball down onto the powder. I then would used a greased cleaning patch to grease the barrel in front of the PRB. I did the same process with my percussion shotgun, too. If I didn't get a shot, the gun was fired before it was transported in a motorized vehicle, to comply with the law.
Only in the past 12-15 years did the Department change its rules to allow lawful transportation of MLers when they were un-primed- ie, the pan was empty, open with the hammer lowered all the way down, or the percussion cap was removed from the nipple and the hammer lowered onto the nipple. The Guns still had to be encased during transportation- no quick shot out the window- to discourage "road hunting".
I now consider it quite the luxury to be able to carefully load my MLers at HOME, in good light, with warm hands, etc. Doing things "the Old way", wives tales or not, resulted in No hang- fires, and No misfires. Other friends with whom I have hunted, over the years have shaved corners, and have had these problems. I tried to ignore these old rules once- at a postal match held on a very Hot, very humid July Saturday, at a club set down in bottomland, surrounded by tall trees, so that NO wind helped to move the moisture. It was like shooting in a SAUNA. I failed to dry my barrels properly, and paid the price with misfires, and lost birds. It took me half an hour to clear and clean the barrels to get the gun operational again. I made sure to clean AND DRY the barrels well, after each shot- checking the cleaning patches by feel to see how "dry" the drying patches were. When there was a doubt, I used another drying patch down the barrel. It was the one time that I have had to make more than a FEW adjustments to my loading procedures with my shotgun.
I am sure that your experiences and those of others may vary from my own. Its not that unusual. When I give advise here, I assume the worst scenarios, and think of the worst situation I have had loading and shooting my guns, that required multiple modifications in my standard loading practices. Then I write giving that advise.
I should ALWAYS include a cautionary comment, that tells folks that there are NO hard and fast rules- unless you consider it a rule to assume NOTHING. READ YOUR SPENT PATCHES, always. That includes Cleaning patches. They tell what the condition of your bore is in, depending on changes in temperature and humidity. If you don't use a cleaning patch after each shot, you can't know the condition of the barrel, and you are "Loading blind".
I recommend running a cleaning patch down the barrel each morning after the gun has SET outside all night, just to find out what went on it that barrel over night. If the patch comes out wet, chances are that whatever wet the bore has also had that opportunity to dampen the powder, too.
If there is any sound advice, its to be READY to change your loading and cleaning practice if there is a change in what your cleaning and shooting patches tell you. If you don't change, the gun may "hiccup" on you.
When I hunt in below 32 degree F. temperatures, the air is basically dry- or at least the RELATIVE humidity is so low that patches in a cold barrel come out dry. However, as soon as the barrel is shot, the heat from the burning powder heats up the barrel, moisture- even as little moisture that there is in very cold weather-- will Condense on the inside of the barrel. It should condense on the outside, too, but the cold, dry, air surrounding the outside of the barrel whisks the moisture away as fast as it might condense, there.
Thanks for the comment. It gets people thinking. If there is anything people should know about shooting BP Mlers, its that this is a Thinking man's game- not something you can do mindlessly. :hatsoff: