The concern is that a person may have a hangfire and think their gun went off. The shooter puts the muzzle in his mouth and instant lobotomy. Hangfires are real, they do happen and I have experienced them.
This prohibition is found at formal ranges. It isn't beyond reality that with a number of people firing black powder at once, and at a match with a lot of excitement, somebody might not be able to see the difference between his or her gun going off and make a mistake. The other reason is for a Range Safety Officer, having to monitor the actions of several shooters at once, they cannot be expected to know each and every shooter's status while reloading, so keeping the muzzle away from one's face is better for the RSO and avoid a lot of unnecessary "cease fire" calls.
Hanshi wrote: I do blow into the barrel by cupping my hand around the muzzle and blowing into my hand.
This has been my practice for many years, and it does improve the reliability of my rifles, after many years of live firing experience. Since my hands are going to be over the muzzle when loading the rifle or gun, it's no less safe for me to cup the ring and little finger of my left hand over the muzzle and blow into my hand from the index finger to provide the air.
Oh and one does not put the actual muzzle into one's mouth, even when not using a cupped hand.
Vomir le Chien wrote: ADDHOC question: What if a new comer see you blowing down the barrel but didn't know all the other steps to do/things to look for??? And/or how to do it in a safe manner!!!! I/We/You, could be indirectly responsible for a very bad day,for both them and us.
Well even if the practice isn't used, the new comer has many steps that they may not know...
...don't pour directly into the barrel from the powder container...
....use a powder measure meant for that gun or rifle....
...use the proper amount of powder for that gun or rifle...
...Don't use 4Fg in large bore guns main charge...
...don't prime the pan before loading as the military reenactors do when shooting blanks....
...Don't use smokeless powder....
....ensure the bullet is seated on the powder...
...any of which, can result in a very bad day for the new comer shooter. I am not responsible for the understanding of anyone that I am not training, so "indirect responsibility" is a term with contradictory words in this case. Either I am responsible for teaching the person, or I am not. Since I have no direct control over any other person that I am not training, I cannot be responsible in any way. I have no way of knowing the level of attention given to me by a bystander. The same as if the next door neighbor kid who has seen me drive off to work every morning, and takes his parents' car, in an unsafe manner and wrecks, I have no way of knowing what he's learning from watching me, nor do I have a responsibility that what he sees he understands.
LD