As a matter of fact, I had that happen about a month ago. First time in 49 years of shooting front loaders. It was an interesting growing fountain of sparks from the muzzle as it burned. Also one of the only times in my shooting life I did not blow down the barrel. Nothing that would hurt anything, but it sure did point out to never load from the horn, which I NEVER do!I will start with I always use a separate powder measure to charge the gun, no exceptions. That said, In my 45 yrs shooting smoke poles, I have never seen a charge go off due to an "ember" in the barrel from the last shot. Has anyone had first hand experience with this and if so, what were the particulars?