William, the manufacturer has 12 round magazines but pricey at $79.95. if interested just Google the item number ( HKP-18672 ) and it's the first website. Hope this helps.

Yes 10rd magazines are in stock here, that 1st link maybe a fake store the next 2 down I've made purchases from and are legit.
https://gun.deals/search/apachesolr_search/642230244269
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Less then $50 bucks at the 2 stores that I know are legit. Much better price then the other links provided

William, yes but kinda expensive : - https://tombstonetactical.com/product/magazine-hk45-compact-45-acp-10rd-black