WTK: ETS Glock 20 10mm 30-Round Extended Magazine in a CMMG Banshee

I don't have the 10mm mags but I have some of the 9mm extended mags. I have the 40s and 31s. So far both have worked in my AR9s. They work in my keltec 2ub 2000 too but they don't drop free in that gun.

I bought magazine extensions for Glock 20 magazines from Kriss to use in my carbine. They are designed to work on a Glock 20 or a Kriss. They might work for you. Check out KRISS' website.