A folding firearm comprises a stock supporting a receiver, the receiver defining a bore for receiving a first end of the firearm barrel. A forearm is operably pivotally connected to the stock. The forearm includes a barrel securing mechanism having a securement member. The firearm barrel has a surface adjacent to the first end for engaging the securement member. The securement member is matingly engageable with the surface of the barrel. The securement member, in response to pivotal movement by the forearm, moves into engagement with the surface to urge the first end of the barrel into the bore of the receiver when the firearm is pivoted into a firing position. The firearm also includes a locking mechanism capable of selectively locking the forearm in the firing position.

An over-and-under shotgun apparatus includes a radius track which serves as a hinge for articulating the barrel portion of the shotgun apparatus relative to the receiver/stock portion of the shotgun apparatus. The radius track is defined by a female or concave portion formed on the monoblock attached to the shotgun barrels, and a male or convex portion formed on the frame or receiver section. The radius track defines a pivot axis that is spaced from the radius track. The radius track provides a substantial surface area sufficient to absorb all of the recoil force generated when the shotgun is discharged. No additional abutment surfaces are needed. A further aspect of the invention involves a novel trigger assembly, including a striker which moves toward the front end of the firearm when the firearm is cocked, and moves toward the butt end of the firearm when the trigger is pulled to discharge the firearm. Yet another novel aspect of the invention relates to a four-position safety switch for selecting the firing sequence of the upper and lower barrels.