Alright, fellow gear geeks and tacti-cool foam-flinging unicorns, here's a PSA about a molle-mountable shotgun scabbard that I found on Amazon. Link for reference:
Because I'm a dork, I am building a somewhat over-the-top loadout, and next on my list was a back-mounted scabbard for a tertiary blaster, preferably shotgun-esq. I selected this particular one after some research on size and retention. This one was also designed for short shotguns, which led me to believe that it would work better with blaster-sized items than the other, larger options available.
Unfortunately, as shown in the photos, the size is a smidge too small. I tested it with multiple blasters, but none of them fit comfortably enough for a smooth mid-battle draw. The closest fit was the Liberator, but it was still tight. All the pump action blasters needed to be printed prior to insertion, or else risk improper priming and jams.
I will be returning this one (hooray for Amazon) and trying again with a different blaster scabbard. If anyone is interested, I can post results here. Thank you for coming to my TED Talk
EDIT: Oh yeah, photos. I point out some high-tension address on the grips that cause binding during insertion and extraction. Various blasters shown.