Stern Defense makes an adapter to use M&P magazines. The other option would be to find a AR-15 lower that specifically takes 45 ACP Glock Magazines. That would probably be the most ideal setup as you can get Kriss Vector Extensions to get more capacity.

Good evening to you!! You will need to get a Glock style adapter and use Glock magazines and drums. Hope this helps. Have a good rest of your day.
🇺🇸🇺🇸 'Merica' 🇺🇸🇺🇸

Hi Wayne, you will need a .45 ACP magazine adapter. The upper is compatible with various .45 ACP magazine adapters, allowing you to choose the one that best suits your needs. The magazine depends on the adapter you choose.
See article here >>> civil-war.net/tacfire-45-acp-complete-upper-assembly-review/
Stay safe & have a great day!

Hi Wayne and welcome. This works with Glock/Glock Style double stack .45ACP Magazines and Drums: budsgunshop.com/search.php/type/gun+magazines/caliber/10000572-45+acp/q/glock+45acp+magazine/sort/best-selling --------------- Cheers, stay safe and happy holidays!