All Model 185 variants have the following features in common:
- Bolt action. Operates in same fashion as bolt-action rifles. In fact, Mossberg's original bolt-action shotgun designs derived much from Mauser bolt-action rifles which had been custom converted into smooth-bore shotguns.
- Chambered in 20 gauge x 2.75"/70mm. They will not accept 3"/76mm shells. The original D variants may also have accepted 2.5" shells, but those are no longer manufactured.
- Removable box-type magazine holds 2 shells, giving a maximum capacity of 2+1 (=3) shells. Magazine is inserted into bottom of receiver just ahead of trigger guard.
- Manual trigger-block safety switch is mounted at top-rear of receiver.
- One-piece stock of American Walnut with Monte Carlo-style comb.
- Trigger guard of black plastic which has molded-in finger ridges along pistol grip of stock.
- Takedown design: by removing the magazine and one screw, the receiver and barrel assembly can be separated from the stock and trigger guard assembly to enable easier cleaning, storage, and transportation.
- Smooth barrel without sighting rib. Uses brass bead front sight along with what could be described as a 0.25"-long "rib" mounted near the breech for use as a rear sight.
- Model 185 shotguns were manufactured from 1947 to 1964, so most - if not all - do not have serial numbers as those were not mandated until 1968.
Model 185K-B: Made 1955 to 1963.