i recall seeing moroccan camel mounted warriors charging across a field during a celebration and suddenly firing their jezails very smokily into the air. didn't seem to phase the camels at all. they get used to it in training (or get eaten if they don't).
anyway, looking for a video of this (i failed to find one) i found this photo from an aussie war memorial site, it's from the imperial camel corps.
https://www.youtube.com/watch?v=07JGpardvLU
also see
https://www.awm.gov.au/collection/F00042/
it has a section where the guns carried by the camels are re-assembled and mounted on carriages and fired. the two-part barrels are interesting. they appear to be breech loaders too. starts at 01:42-ish