There are lots of questions like this. I just recently received a MAX 10/45 MK 1 and haven't had a chance to shoot it yet. I have wondered about a drum fed upper in 45 but I suppose that drums might be limited to Thompson drums which are expensive. Also, the weight might be tremendous with 50 or more rounds of 45. Not to mention that some folks have made extended GG mags already. I guess that when a line of products like the Lage products are reliable and backed by a dependable company, we can want all kinds of variations from them. I'm sure others are in the works. Time to save up some cash.
WKM
WKM

