Thank you so much Ed, for the excelent observations. I must say i am very pleased with your precious input.
Yes, the absence of a lip on the fire hole also drove me to realize this piece wasn't a signal mortar or some sort of upright thunder mug ... together with the fact that it doesn't widen at the basis.
So a shooter (hand canon) it will be, given that no compelling evidence proves otherwise
.
Thanks again
Fernando