FWIW, here’s the approach I’ve settled on over the years:
1) I load before I leave the house, I put a couple layers of masking tape over the muzzle, I put a piece of G.I. dry adhesive duct tape over the vent, leather hammer stall over the frizzen...no chance of accidental external ignition source getting to it.
(I slide the long gun into a padded case for the drive just to protect it)
2) When I’m ready to hunt, I pull the tape off the vent and stick it to the lock’s off side for use on the return trip home;
3) When I get back to the house, I pull the load, wipe the bore, take the Flintlock into the house to warm up and completely dry out, load fresh for the next hunt whether that’s the next day, next week, etc.
HALF-COCK SHOWING THE STRIP OF TAPE OVER THE VENT / PAN,
HAMMER DOWN VIEW WITH TAPE OVER VENT / PAN
LOCK’s OFF SIDE SHOWING TAPE STORED FOR USE ON THE RETURN TRIP HOME