I ended up putting the stock in the mill, and took a few thou off the front of the mag well on the Sage stock. New 30s go in and out as easy as the 20s now. A hand file would work just fine for those without access to an end mill. Just go slow, it won’t take much.
Awhile back I spoke with someone at SAGE. They offered to modify the stock if I was willing to send them my gun. Shipping isn't cheap. Knowing that the issue can be remedied with a file is good news.
Nope. Sage stocks are not machined fully to accommodate 30rd mags. You may need to file the front of the magwell to get enough clearance. I had to on mine and now 30s go in easy and detach.