Cap won't budge 😤 starting to loose faith in Google almighty, someone out there must of taken the end off a 9.5xp and taken a photo or even written a small comment!! Can think of several possibilities - corroded on just slides on ( but have knocked it about enough to over come that), it's threaded and corroded (no signs of twisting yet), some t@$t has stuck it on with adhesive.
Rant over, thank you for reading.