I have the X3 Lo Drag. 6.5CM RPR with APA break and Magpul PRS stock almost fits completely, including a Vortex PST and Atlas Bipod (pretty uncommon setup, I know). Stock sticks out about 6" from the top of the bag. Perfectly easy to slide in and out, with bipod folded forward or back
16" barreled AR with stock in the fully shortened position disappears completely.
Haven't put a shotgun in, yet.