I don't believe this particular rifle has been used for anything in several decades. You know how, after setting in a closet, under a bed, in the rafters or wherever, the grooves become filled with dust, it mixes with whatever oil or moisture might be in the bore and after decades, it petrifies....or nearly so. That's what the gunk in this bore appears to be and what the resultant pits are from...with the always probability of mercuric priming.. Even with the bore, it's growing on me but, I have an ineradicable fondness for old rifles, foreign and domestic.
Still...I find the ejection....amusing if nothing else.