The first Stevens 520 appeared in Stevens' 1909 Catalog No.
52 and was also offered for sale in the fall 1909 Sears & Roebuck catalog.
It is easily recognizable by its "humpback" double receiver.
 It has a round slide release knob on the left side of the receiver, a visible breech locking bolt on the top of the receiver, and base models have a rounded pistol grip on the butt stock.
The fore grip is ringed and uniform in size.
The trigger housing is retained with three screws and the safety is a lever located inside the trigger guard in front of the trigger.
The cartridge stop is a rocker design with a set screw on front right side of the receiver.
There were other models including a Model 522 trap gun and the 525, 530, and 535 with increasing levels of engraving and stock quality (some straight grip) and fore grips.
Internally there is an inertial slide release block that is affixed to the inside of the receiver.
 This inertial release uses the recoil of a discharged round to unlock the breech.
The action was designed to only unlock after firing or with use of the slide release and not by dry firing like many modern shotguns.
 All model 520s were only offered in 12 gauge until 1928.

Around 1918, Stevens provided a 520 trench gun prototype to the US military for service in World War I. Supposedly, several examples were made but no known examples survive.
It had a unique two piece heat shield-bayonet lug.

When Savage Arms purchased Stevens in 1920, the Model 520 was updated, incorporating several design changes that were emerging prior to 1916.
 These include a relocated slide release button, moved from the left side of the receiver to the left side of the trigger plate, and a redesigned inertial slide release, incorporated into the design of the trigger plate.

In 1925, the Model 520 first appeared as a store-branded gun when it is sold as the Ranger Repeater Model 30 by Sears and the Western Field Model 30 by Montgomery Wards.
 Around this time the inertial slide release blocks were removed and replaced with a spring that provided forward pressure on the slide release.
 Guns made after this time can be unlocked after a dry fire with forward pressure on the slide.


In 1928, the first sub-gauge Model 520 was introduced when a 16 gauge option was offered.
 It was followed in 1930 by a 20 gauge Model 520.

The Model 520 last appeared in a Stevens sales publication in 1928 and 1929 (Catalog #57) but remained in full production until 1939.
 During this time it was sold as a store branded gun and under Stevens' budget line Riverside Arms.
 The shotgun went through several design changes during this period.
 Most notably was a redesign of the cartridge stop in 1933 and the relocation of the safety, from inside the trigger guard to behind the trigger in 1937.

Model 520 production ended in 1939 and it was replaced by the improved Model 520A in 1940.
The first Stevens 520 appeared in Stevens' 1909 Catalog No. 52 and was also offered for sale in the fall 1909 Sears & Roebuck catalog. It is easily recognizable by its "humpback" double receiver.  It has a round slide release knob on the left side of the receiver, a visible breech locking bolt on the top of the receiver, and base models have a rounded pistol grip on the butt stock. The fore grip is ringed and uniform in size. The trigger housing is retained with three screws and the safety is a lever located inside the trigger guard in front of the trigger. The cartridge stop is a rocker design with a set screw on front right side of the receiver. There were other models including a Model 522 trap gun and the 525, 530, and 535 with increasing levels of engraving and stock quality (some straight grip) and fore grips. Internally there is an inertial slide release block that is affixed to the inside of the receiver.  This inertial release uses the recoil of a discharged round to unlock the breech. The action was designed to only unlock after firing or with use of the slide release and not by dry firing like many modern shotguns.  All model 520s were only offered in 12 gauge until 1928.
Around 1918, Stevens provided a 520 trench gun prototype to the US military for service in World War I. Supposedly, several examples were made but no known examples survive. It had a unique two piece heat shield-bayonet lug.
When Savage Arms purchased Stevens in 1920, the Model 520 was updated, incorporating several design changes that were emerging prior to 1916.  These include a relocated slide release button, moved from the left side of the receiver to the left side of the trigger plate, and a redesigned inertial slide release, incorporated into the design of the trigger plate.
In 1925, the Model 520 first appeared as a store-branded gun when it is sold as the Ranger Repeater Model 30 by Sears and the Western Field Model 30 by Montgomery Wards.  Around this time the inertial slide release blocks were removed and replaced with a spring that provided forward pressure on the slide release.  Guns made after this time can be unlocked after a dry fire with forward pressure on the slide.

In 1928, the first sub-gauge Model 520 was introduced when a 16 gauge option was offered.  It was followed in 1930 by a 20 gauge Model 520.
The Model 520 last appeared in a Stevens sales publication in 1928 and 1929 (Catalog #57) but remained in full production until 1939.  During this time it was sold as a store branded gun and under Stevens' budget line Riverside Arms.  The shotgun went through several design changes during this period.  Most notably was a redesign of the cartridge stop in 1933 and the relocation of the safety, from inside the trigger guard to behind the trigger in 1937.
Model 520 production ended in 1939 and it was replaced by the improved Model 520A in 1940.
Stevens Model 520/620