Factory 20 rounders are here: https://us.hkwebshop.com/hksto...-Magazine/p/50239330
Well, it's cheaper than buying a 15 rounder and getting a TF extension. Hopefully it'll work with my HKParts EDC Magwell. The bottom is just a plastic cover for the metal tube, so I could see making a couple of 170mm-esque mags for USPSA down the line once the proper springs come out for them.