Thank you for input Norman,
I think that is more than proven that, the blunderbuss bell mouth purpose was for spreading the shot, is pure fantasy. A more realistic evidence was the facilitating of the load; We may also consider that its appearance would intimidate the guys in front of it ... be them bandits or a mutiny crew.
But these untruths belong in history with the same firmness as real facts.
This reminds me i have the same conviction about the so called sword breaker (rompe puntas) in some (many) cup hilted swords. I just can't buy the idea that you could manage to catch the adversary's sword tip with such reduced cavity and, even more implausible, bend it enough to break it
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