Wellll, the big brown truck dropped off a E&R bag for me today and while it's beautifully constructed it'll be going back to Mayflower tomorrow since it's about 2/3-3/4 of the overall size I was hoping it would be. Given the lack of measurements available online, the misunderstanding about size (story of my life...) is understandable so I'm posting some pictures so that other folks in the market for a bag like this can get a better idea of how not-large the bag is. I won't post a photo of the outside of the bag--those are available on Mayflower's site.
First shot: Outside of the bag with a PMAG (we know how big those are) for comparison. The bag is laying flat on the floor so it's "collapsed" outward and hence, looks a big big. For an additional reference, the second picture is of the bag with a standard 8 1/2" x 11" sheet of paper (tuition reimbursement form from my work) on top.
Wearer's-side of the middle interior pocket. The loops are of an elastic material so they can stretch to hold long/thin objects (chemlights, maybe some pistol magazines, etc)
Depth of the interior middle pocket. This was a hard image to get lit properly (Stickman I am not...) but without anything in the interior slash pockets, the middle isn't much deeper than a single PMAG is wide. The main compartment of the bag is subdivided into three sections--an outer slash pocket lined with loop-side velcro, the middle compartment that has a field of elastic loops on the wearer's-side, and a close-in slash pocket that is plain nylon. For an additional size reference, I couldn't fit my iPad with it's Otterbox case into either of the slash pockets and could only finagle it into the main compartment with some difficulty.
The one Youtube vid I found about this bag made a big deal out of being able to fit AR magazines in the loops of the outer pockets and while metal magazines fit, you can't use them for PMAGs without the magazine body sticking up out of that compartment and being unable to velcro that compartment shut. While me going to a long gun while carrying this bag means things have gone very very very badly and so I shouldn't need to worry about staying discreet at that point, I'd rather be able to keep the magazines out of sight if I'm hoping to remain a little bit "gray" before all hell breaks loose.
This part I like--the cover flap is lined with clear plastic so you can use it for maps/other papers that you might need to reference when it's raining but don't want to get them wet. For size comparison I've used a standard 8 1/2" x 11" sheet of paper (that same tuition reimbursement form from work)
The side pockets are also fairly small--I got a regular 12 oz. can (355 mL, for those folks living in Metric Land) to fit and could easily get the flap cover in place. A standard 24 oz (710 mL) bottle from Liberty Bottle Works would fit with some difficulty but there was nooooo chance of the flap closing to secure that $25 bit of schwag, dammit...