The fact that the letters “HE” are found together in the markings causes me to have reservations about this piece of ordnance:“C/97 98, M, 1903 KAB SRU HE 69” This by itself is enough to have me call the ordnance folks to come get it, or at least see if it is in fact high explosive. Its always the ones that are brought home by a relative long ago that end up going bang. It would be nice if the O.P. would make another appearance. Collectors today still come across pieces that turn out to be live, and have been sitting quietly in a box or on a shelf for decades, till Gramps passes away, and they start to go through things and find his old souvenirs. The same goes for relic hunting on the Civil War sites here in the South, if one digs up a cannon ball, it may be a solid shot, or a shell filled with blasting powder. Not always easy to tell the difference either after 150 yrs in the dirt.
After Wars are over, it was the practice of manufacturers to sell ordnance that had not been completed, and shipped, to firms that then sold them as collectible specimens. They had all the mechanical parts, but no energetics, and were very safe to keep. (unless dropped on your toe) These are still extant, and enjoy some popularity in the States. Its always the “Bring backs” that are the problem, no one really paid attention to such things during WW I, and II. so stuff got sent home, brought home, as war trophies, and there it sits waiting. (Like the Butterfly Bombs featured in an episode of my favorite War show Danger UXB, where little Farqhuar had one stashed in his dresser drawer)