I would say yes but the question is do you really want to and I Would still treat it as loaded if you did
I have in the past left a hunting load in for 2 nights and still had it go off with little delay.
If by chance you’re worried about condensation getting into the charge put a peace of plastic rap over the nipple and let the hammer down.
I recently bought one of those Co2 dischargers and it works great, simply pops the round right out in my flintlock. I also tried it on a friend capper this fall and it worked just as well.
I often leave a load in my gun during hunting season. The key is to keep the load dry. I hunt Utah, and the weather here is pretty dry so I usaully don't have to worry. However, if I'm hunting in rain or snowy weather, or there is high humidity (over cast), and a lot of condesation in the morning, I'll start with a fresh load.
I never leave a cap/primer on a loaded ML.
Do I treat the gun as loaded? simple answer yes! Do I treat the a gun I just got through cleaning and know is unloaded, as loaded? yes! But I don't think that is what you were asking.
Here in Utah a ML is not legally loaded until you put the cap/primer on the gun. But this could vary by state, so check you local regulation. So from a legal standpoint you can do what you want.
Safety- besides the obvious, if you have a load in the barrel but the gun isn't capped, you must gaurd against sparks or flame from getting to your load. Things like campfires, smoking, heaters all could pose a risk of touching off your load if you got your gun too close. Otherwise IN MY OPINION a load in the barrel, but not capped, is very similar to a cartridge in the magazine.
I always leave my gun (a caplock) loaded until I either get a shot at game or the season is over. Whether I fire the gun on the third day of hunting (as I did this year) or at the end of the week it has never failed to fire immediately.
Always treat the gun as though it is loaded. I also always put a piece of electrical tape over the end of the barrel after loading in order to keep it clean.
My gun is a traditionally styled Lyman Great Plains Hunter in .54 caliber.
There it sits. Alone and forgotten in a desk drawer or maybe in the bottom of your hunting pack. The lowly compass. Primarily initially replaced by the hand held GPS and now even by the new “smart” cell phones that include GPS, electronic compass – even real time imaging on aerial maps! Once the friend of every hunter and now the companion of few. It is not glamorous or glitzy, that is for sure… no bells and no whistles. Aaaaah, but let’s not rush to forget our...