Reddit mentions of NC Star Competition Range Bag, Urban Gray

To my knowledge, as u/ExpatJundi said, it doesn't have to be rigid. I'm pretty certain it can just have locking zippers, especially since that's what I primarily see at USPSA competitions and other range gatherings.

I had been looking at the Plano pistol cases, but ended up saving some money by going with this bag... Not top of the line by any means but I've been very happy with it thus far.

https://smile.amazon.com/gp/product/B00I1RZ7EI/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

EDIT: According to http://www.masslive.com/politics/index.ssf/2012/12/a_primer_on_massachusetts_gun.html

"Transporting a firearm in a vehicle: The same licensing restrictions on ownership of various firearms applies to transportation of such guns. But generally speaking, all rifles and shotguns must be unloaded when in a motor vehicle. Handguns and large-capacity firearms left unattended in a vehicle must be unloaded and kept in a locked case, locked trunk or other secure container. Muzzleloading or other Black Powder firearms must also be unloaded."

I have this bag and it works great—super sturdy and well-constructed, and the shoulder strap easily handles the weight. It is decently padded and has rubber feet on the bottom. The M1 is a hair tight to get into the main compartment, but it fits perfectly once inside (the main compartment dimensions are nearly perfect for the M1 with a couple inches to spare lengthwise). My Vortex Rac3 (75%) or New Poker II (65%) fit comfortably in either side compartment (not sure if a TKL would fit though). If you have a headset that fully folds up, that fits nicely in the draw-string end pouch/bag (Sennheiser PC350SE). The side pouches also have an interior molle web that is great for keeping your cables nice and organized. Definitely recommend it!