Yeah, a replaceable rubber cap would be very nice, but if we replace it by the user, we can always break the very delicate contacts of the rotary mechanism.
At first I thought about two rubber caps - an inner one, which can only be changed with a complete disassembly of the tail, and an outer one, which will be fastened with a threaded ring.
But if something could pierce the first rubber cap (metal shavings), then it will pierce the second cap as well.
Then another idea came - a metal cap made of steel (optionally titanium). And everything will be inserted from the inside, that is, Henry will fix it. If you choose the right contact patch and membrane paterial (fluorsilicone example or kalrez), it will last forever and is protected from wear, except for very advanced cases of contamination.
Just a mental diagram, without a rotating stuffing.
This can slightly increase the size of the cap in length and weight, although I have not seen those among HDS lovers who complained a lot about weight, unlike Zebra lovers :grin2: