As someone who owns an M10B, and has read up on them a lot ... they're not entirely a great weapon.
- not suited for left-handed shooting at all
- won't work with low-power 12 gauge ammunition
- the flashlight bulbs (back in the 1980s) broke quite often
I think that in modern times there are short shotgun options better than the M10B -- especially if you're running a campaign with the Project not being frozen until the early 21st Century.
If we consider the (modern) requirements for an equivalent to be:
- short length or folding stock (for hauling through vehicle hatches)
- capable of being used one-handed
- uses 12 gauge ammunition
- reliable
- having an accessory rail, or can easily mount lights, lasers, etc.
... what modern firearm fits all of that? The SPAS-12 doesn't have a rail ... they've been out of production since about 2000.
--
Michael B.