I am a cannon owner, reenactment gun captain, and the one almost always handling the ramrod.
There was much discussion on another list about thumbstalls, and I agree the thumbstall is of minimal value, but it does help reduce risks by keeping any ember as cool as possible.
The suggestion was that there was an ember trapped in the vent, and that the cure is to clean the vent before each firing. Probably not a bad idea but I suspect that was not the problem and would not have prevented the accident. More likely, embers were trapped in foil that had not been cleaned out. I know from experience that it’s easy to miss.
The real problem seems to me to more like a combination of 3 things.
1) Improper cartridge – the foil cartridge must have at least two layers of heavyweight foil all around. All around and triple sure the part covering powder has 2 layers which means that most will have 3 or more. I am confident that there is no ember that will ignite powder through a double layer of heavy foil. Nor do I believe a properly made cartridge will burst open (if the ramrod fits the barrel). I bet a quarter the cartridge was incorrectly made. This is top of the list.*
2) Insufficient worming and swabbing. There is lots of time to worm twice and at least once after the last bit of foil was extracted. There is lots of time to swab wet twice and once dry, with different tools. The wormer/searcher especially should be trained to recognize by feel and sound the presence of residual foil. However, leaving a pool of water from over-enthusiastic swabbing is NOT a good thing… that makes it more likely that damp priming powder will survive the shot to burn later – a good dry sponging is also a safety step.
3) Insufficient time passing. Most embers will die in seconds…. (Since there is no organic matter in the tube but powder, right? So only (damp) powder and residual carbon is possible, right? Double check, no wadding…. Right? ) Anything close to most field rules of 3 minutes between shots almost assures a cool ember-free tube, even if the swabbing is done poorly. If the worming and swabbing is done well and carefully, it will take up a good two minutes, so no reason to rush that job.
Cleaning the vent, if done, needs to be done before swabbing . If this were done after swabbing it would just knock a live ember (if such existed) into the barrel. However, Somehow I can’t see a scenario where embers would settle back into a vent – if there is no wadding and no linen bag, only damp powder could make up the substance for an ember, and how would that settle UPWARD, after the blast of the charge rather thoroughly cleared the vent? I suppose we can’t rule it out 100%, but lets not ignore the higher probabilities while addressing the low probabilities.
*About foil, once a long time ago a couple of us destructive kids decided to reenact a spaceship fire – we did not want to destroy our valuable GIjoes or spaceman action figures , so we used a Barbie or other doll. We created a foil space suit , partially for looks, but partially so that the destruction would not be instant. We doused the doll in flames, and even applied a propane torch. We then pealed back the foil suit to inspect the damage. To our horror, the doll had been completely protected by the foil suit – barely a mark on her, if that. The point is, 2 layers of foil really does a good job against fire and embers, short term.
