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https://www.sjscycles.co.uk/gear-spares/sram-apex-1-b-adjust-limit-screw-for-rear-derailleur/ ?
If it were me I'd take the screw out and show it to my friendly local engineers' merchant, working on the assumption that it's unlikely to be something terribly exotic; I'd suspect this would be the #tester_approved method, save that he probably knows exactly what size and pitch it is already...
I have bent the B-adjusting screw on an old Sram Apex rear derailleur. Is it possible to buy a new screw? Are they a universal fit on Sram, or in general? Or does it mean replacing the derailleur? It works fine with the bent screw in currently, but doesn't seem like a long-term great idea. Thanks in advance of any help.