The Mossberg Model 500: History & Dismantling
Designed and first marketed in 1962, the Mossberg Model 500 shotgun is a popular weapon, no doubt because of its well-balanced combination of affordability and quality. The “modular” nature of the Model 500 product line certainly doesn’t hurt either, and a dizzying array of gun options and actions allow users to turn a single Model 500 into a full-size cruiser. pistol grip or a 28 “barrel bird. pistol by simply changing a few parts.
the Mossberg 500 uses an aluminum receiver to reduce weight. Inside the Model 500 latch is a steel latch bolt that engages a recess in its steel barrel extension for steel-to-steel locking.
The barrels are interchangeable in specific gauges and were produced with and without ventilated ribs; open sights, ball sights and full scope bases; in lengths from 18 1⁄2 “to 32”; C-Lect-Chokes and provision for screw-in Accu-Chokes; smooth or ribbed bores and even in a .50 caliber. striped muzzleloader version. The stocks and handguards, originally in regular walnut, are also found in checkered birch or synthetic, some with a black finish, others with camouflage patterns. Stocks with interchangeable combs or with shell holders for quick reloading were available, as were points with integrated laser sights.
The Model 500 owes much of its popularity to its military and police service. First used in 1979 by all major branches of the United States Armed Forces in the guise of the Model 500, requests for increased ammunition capacity and other modifications resulted in the Model 590 shotgun (a variant Model 500) which was adopted in 1987. This represents standard pistol accessories such as swivels, barrel heat shields and pistol grip assemblies which are not shown on the attached “Exploded View”. It represents only the base weapon, the heart of what the factory calls “the Mossberg fire system”.
Start by pushing in the action lock lever (3) located behind and to the left of the expansion box (58).
Retract the front (28) to open the action and check the room, elevator (19) and loader tube (32) to make sure the gun is unloaded. Slide the security button (43) backwards to the “on” position.
Move the front forward until the front of the bolt (9) is centered in the ejection port, then turn the removal screw (56) at the front of the magazine tube (Fig. 1) counterclockwise until the threads are no longer engaged. The Canon (seven) can now be removed by pulling it forward.
Next, place the gun on a flat surface with the trigger housing facing up and push out the pin from the trigger housing (59) from left to right. The trigger housing is removed by pulling up at the rear (2), then out of the receiver (39). Make sure that the trigger (57) is not pulled during withdrawal. Further disassembly of the trigger assembly is not recommended by the factory and should not be required for routine cleaning and maintenance.
Remove the cartridge switch (13) and cartridge stop (14) (3) through the opening at the bottom of the receiver.
It may be necessary to lightly tap the sides of the receiver with a wooden or plastic mallet to release these parts. Slide the front three-quarters back, until the bottom of the bolt slide (12) lines up with the release cutouts on the side of the receiver. The bolt slide is now raised and out of the receiver (4).
Then the bolt assembly is slid forward through the opening in the front for the barrel assembly and out of the receiver (5). The factory does not recommend further disassembly of the bolt.
Make sure the safety is in the back or “run” position before attempting to remove the riser assembly. Lift the front section upwards and apply pressure on both sides of the lift arms (Figure 6) until the pins are no longer touching the sides. Lift the elevator from the bottom of the receiver.
The action sliding tube assembly (5) is now removed by sliding it forward and disengaging it from the magazine tube (7).
Insert an appropriate size screwdriver into the ejection port and unscrew the eject screw (18), then remove the ejector (17).
If it is necessary to remove the stock (52), loosen the upper shoe screw (41) and flip the bottom one. The recoil cushion (40) and spacer (51) are turned sideways to allow access to the original bolt (53). Unscrew the original bolt and remove it from its socket. The stock is now pulled back from the receiver.
Reassembly is carried out in the reverse order. Note that the hammer must be in the fully cocked position for reinsertion of the trigger assembly and that the safety must be in the “on” position to reinstall the bolt assembly.