Not exactly true. R&R Targets has them listed on their site as 20rd tuned. The mag is a franken magged SGM that is created to work with their magwell and available as a special order only for a very reasonable price of $275. I will not be ordering any. To the op I am almost positive that there was a coupler made for the SGM mags that would allow you to couple two mags together. You could use a SGM 8and a 10 couple them together fill the 8 with silicone, concrete,lead, dogshit or whatever. and you would achieve your goal and remain legal. Good luck; just don't send me pictures.