A combined firearm receiver and rail includes a handguard rail and a receiver housing disposed within the handguard rail. The handguard rail includes one of a takedown lug clearance slot, a handguard magazine port, a handguard continuous rail, a handguard ejection port, an attachment location, accessory attachment points, a handguard charging handle latch retaining slot, a charging handle housing, a charging handle guideway, a bolt catch clearance slot, a barrel cavity, a receiver cavity, an exhaust port, and a handguard section. In one variation, the handguard section does not come into physical contact with a barrel or a barrel nut of the firearm.

A handguard grip assembly has a connector to be fixed to a barrel of a rifle, the barrel having a barrel axis, a grip having a grip axis and adapted to be held by a user of the rifle and a flexible joint connected between the connector and the grip for allowing the grip and grip axis to pivot to any angle with respect to the barrel axis.

A handguard grip assembly has a connector to be fixed to a barrel of a rifle, the barrel having a barrel axis, a grip having a grip axis and adapted to be held by a user of the rifle and a flexible joint connected between the connector and the grip for allowing the grip and grip axis to pivot to any angle with respect to the barrel axis.

A firearm slide accessory includes a charging handle attachment including a first member and a second member. The first and second members are formed with one or more mounting holes through which pass one or more fasteners. The first member includes an accessories rail for mounting accessories thereon. The accessories rail extends in a firing direction forward of at least one of the fasteners.

A firearm slide accessory includes a charging handle attachment including a first member and a second member. The first and second members are formed with one or more mounting holes through which pass one or more fasteners. The first member includes an accessories rail for mounting accessories thereon. The accessories rail extends in a firing direction forward of at least one of the fasteners.

A firearm as disclosures herein comprises a main receiver body, a barrel, a breech bolt structure, a buffer assembly, a trigger group assembly, a bolt catch and at least one of an auto-sear, a magazine adapter and a breech bolt anti-rotation structure. The main receiver body is preferably of a monolithic construction whereby the handguard and breech bolt carrying bore can be manufactured from a single piece of material. The auto-sear is tripped by engagement with a buffer of the buffer assembly. The magazine adapter has an exterior surface structure engaged with a mating interior surface structure of a magazine well space of the main receiver body. A distal end portion of the breech bolt anti-rotation structure is engageable by the buffer for limiting forward travel of the buffer when the barrel is detached from the main receiver body.

A firearm as disclosures herein comprises a main receiver body, a barrel, a breech bolt structure, a buffer assembly, a trigger group assembly, a bolt catch and at least one of an auto-sear, a magazine adapter and a breech bolt anti-rotation structure. The main receiver body is preferably of a monolithic construction whereby the handguard and breech bolt carrying bore can be manufactured from a single piece of material. The auto-sear is tripped by engagement with a buffer of the buffer assembly. The magazine adapter has an exterior surface structure engaged with a mating interior surface structure of a magazine well space of the main receiver body. A distal end portion of the breech bolt anti-rotation structure is engageable by the buffer for limiting forward travel of the buffer when the barrel is detached from the main receiver body.

An upper receiver assembly includes an outer member with an upper rail and an inner member with at least one of a pivot pin lug and a takedown pin lug. The inner member is disposed at least partially inside the outer member. The outer member includes an ejection port, and the inner member includes an ejection port. The ejection port of the inner member is at least partially aligned with the ejection port of the outer member.

An upper receiver assembly includes an outer member with an upper rail and an inner member with at least one of a pivot pin lug and a takedown pin lug. The inner member is disposed at least partially inside the outer member. The outer member includes an ejection port, and the inner member includes an ejection port. The ejection port of the inner member is at least partially aligned with the ejection port of the outer member.

Rotatable handles and related methods are disclosed herein. In one form, the handle has a clip member that fits around a cylindrical object and a handle. The clip member includes a track that guides rotation of the handle about a longitudinal axis of the cylindrical object. The handle includes an actuator that operates a braking member which comprises a braking surface that is movable into and out of contact with the track. When the braking surface is out of contact the track, the handle is movable relative to the track when permitting the handle to rotate about a longitudinal axis of the cylindrical object. Rotating the handle about the longitudinal axis of the handle operates the actuator, causing the braking surface to move into and out of contact with the track. Various methods are also disclosed herein with respect to the rotatable handle.