The 9mm Calico is a fun gun and with its bottom ejection port, is entirely ambidextreous. I dislike the flimsy extruded stock or the later fixed plastic stock. It's a natural for a bullpup with a 100 round magazine attached. The weak point of the Calico is the material used for the magazine. It's a bit too brittle and can break if dropped (ouch!). Also, magazine spring tension is crucial to reliability in the Calico (never did figure out how many cranks for a partially loaded magazine).
Another thing nice about the design is that it uses a very simplified delayed blowback (ala HK91/93/MP5) design. Whereas HK went with expensive (and extensive) machining, Calico accomplished the same with less costly methods (part of the bolt may have been machined, but a lot of its wasn't).
If you haven't gotten the magazine loader for the Calico, get one. With practice, you can load a 50 round magazine in less than 15 seconds.
Years ago I visited the factory in Bakersfield and spoke with two of the designers. The factory was actually only an assembly plant and the production of parts was contracted out. They had about a dozen drill presses with drill jigs bolted down. The receiver would be placed in the jig and drilled. The final product was sent outside for anodizing.
Headspacing on the carbine and pistol are slightly different. It's a little longer on the carbine so as to slow down the unlocking time. With the longer barrel, the pressure is higher (or stays higher longer) and to slow down unlocking, they allow the rollers to protrude out further.