Some guys are even filing out the front of the mag well in the lower receiver, to get more OAL in combination with these cutout mags. That's farther than I'm willing to go at this point, but an interesting possibility.

For those who don't know, ASC mags will get you 2.300"+ without any modifications. I still like Pmags better for most things, but you're limited to 2.260" without cutting.