Detailed Remington Wingmaster Assembly Blueprint and Exploded Parts View
Start with securing a high-resolution exploded view chart of the 870 model–focus on parts numbered below 200 for core disassembly. The firing pin (component 12) requires precise alignment; misplacement by even 0.5 mm causes failure to strike. Use a micrometer to verify tolerances before reassembly. Barrel threads (part 9) must be cleaned with a phosphorus-bronze brush–steel brushes strip plating.
Trigger group housing (component 130) contains six critical springs; catalog each by wire gauge (measured in thousandths of an inch) to match replacements exactly. The shell carrier (part 7) pivots on a case-hardened steel pin–apply nitrile-based lubricant sparingly to prevent gumming. Forced extraction requires checking the ejector (part 8) for wear; replace if grooves exceed 0.3 mm depth to avoid stovepipes.
Receiver rails (part 6) demand cross-hatch honing if galling appears–use 400-grit diamond stones at a 30-degree angle. Action bars (component 14) should slide without binding; test by cycling with an empty chamber before final assembly. Magazine tube assembly (part 11) holds a follower spring; verify tension by counting coils–12 active coils at minimum for reliable feeding. Always work on a non-marring surface (e.g., silicone mat) to avoid scratching blued finishes.
Exploded View of the 870 Model Firearm Assembly
Locate the barrel retention screw near the magazine tube–ensure it’s fully seated before reassembly. Misalignment here causes feeding jams in 12-gauge configurations. The ejector spring should exert 8-10 lbs of tension; replace if compression falls below 7 lbs. When disassembling the trigger group, mark the hammer and sear positions with a fine-tip marker to avoid reset issues during installation. Use a torque wrench on the action bars: 15-18 in-lbs prevents slop without risking thread damage.
- Barrel extension: Check for cracks around the locking lugs–tiny fissures worsen with magnum loads.
- Bolt face: Polish the extractor claw chamfer to 0.020″ depth; factory edges are often too sharp.
- Fore-end cap: Apply lithium grease sparingly–excess causes slippage under recoil.
- Stock bolt: Use blue Loctite, but avoid red–over-tightening cracks walnut.
For the feed ramp, radius the loading port edges to 0.125″ to prevent shell deformation. Stainless steel internals require molybdenum disulfide coating; standard lubricants wash off in subzero conditions. If modifying the tubular magazine, shorten the follower spring by one coil for lighter loads–this reduces bolt drag without affecting reliability. Always verify headspace with a no-go gauge after any receiver modifications.
Key Components of the Classic 870 Shotgun Exploded View
Start disassembly by removing the magazine cap (part #182500) using a 5/32″ punch–apply pressure counterclockwise while stabilizing the barrel (part #182600) to prevent thread damage. The action bar assembly (part #174207) splits into left and right rails; inspect both for burrs or wear, as uneven contact with the receiver (part #182510) causes cycling failures. Replace springs (part #182545) if compression falls below 12 lbs at 1.25″ travel.
Critical Assembly Groups
| Group | Critical Parts | Tolerance Check | Common Failure Points |
|---|---|---|---|
| Bolt | Extractor (#176200), Ejector (#174211) | Extractor claw gap: 0.020–0.025″ | Chipped claws, misaligned ejector |
| Trigger | Disconnector (#174218), Hammer (#176203) | Trigger pull: 4–6 lbs | Worn disconnector, bent hammer hooks |
| Magazine Tube | Follower (#182540), Carrier (#174206) | Follower travel: 2.5–2.6″ | Dented tube, cracked follower |
Barrel alignment hinges on the rib (part #182602)–verify true center by dry-firing with a bore-sighter; deviations over 0.005″ at 15 yards indicate bent ribs or improperly seated threads. The fore-end assembly (part #182550) requires periodic lubrication of six roller bearings (part #182555) using Molybdenum disulfide grease, but avoid overpacking, which attracts carbon fouling.
Stock attachment (part #182700) uses a through-bolt (1/4″-28 thread); torque to 25 ft-lbs–loose stocks cause point-of-impact shifts up to 6″ at 35 yards. For synthetic models, inspect the recoil pad (part #182710) for delamination; replace if compression set exceeds 0.1″. The safety (part #176210) should snap audibly with less than 2 lbs of force; sluggish engagement indicates a worn detent plunger (part #176212).
Reassembly Validation Steps
After reinstalling the action spring (part #174205), cycle the slide 10 times–binding suggests misaligned action bars or bent rails. Test the firing pin (part #176202) protrusion with a feeler gauge: 0.045–0.055″ ensures reliable ignition. For extended magazines, confirm the retaining ring (part #182505) seats flush; gaps cause feeding jams. Store disassembled components in labeled trays with silicone-treated felt to prevent galling on steel-on-steel surfaces like the breech bolt (part #176201) and carrier edges.
Gas system maintenance–though non-existent in pump-actions–mirrors the Wingmaster’s vent rib design. Clean the ventilated rib with a brass brush to remove carbon deposits that disrupt sight alignment; ultrasonic cleaning at 60°C for 15 minutes restores original rifling dimensions without damaging the chrome lining. For rare tactical models with ghost-ring sights, verify aperture alignment by bore-sighting at 50 yards–adjustments require a 1/16″ Allen key on the rear sight (part #182604) and a brass drift for the front post (part #182603).
Identifying Barrel Assembly Components in Technical Blueprints
Study the exploded-view drawings first–barrel components are typically clustered near the muzzle end, often labeled with numeric or alphanumeric codes matching a parts legend. Look for thin, elongated shapes with threaded sections or grooves; these indicate the barrel itself, usually positioned centrally in the upper half of the layout. The chamber area may show thicker walls or reinforcement rings, distinguishing it from the narrower bore. If multiple barrels are depicted, note the one aligned with the firing mechanism, which will have distinct machining marks for locking lugs or gas ports.
Trace the barrel extension segment where it interfaces with the receiver. Here, schematics frequently highlight notches, shoulders, or locking recesses critical for headspacing. These details appear as dashed lines, cross-hatching, or dimensional callouts (e.g., “.308 WIN” or “12 GA”) to specify caliber or gauge compatibility. Examine accompanying notes for torque specifications or assembly sequences–these often clarify whether certain parts require timed installation, like a threaded nut or retaining pin.
Decoding Subcomponents and Fasteners
Locate the barrel nut or sleeve, which secures the assembly to the receiver. In blueprints, it appears as a circular or hexagonal block with internal threading, sometimes wrapped around the barrel’s breech end. Check for serrated edges or knurling if the part requires manual tightening; these design elements are drawn as fine, repetitive lines along the outer perimeter. Nearby, watch for a lock washer or set screw–depicted as a small dot or perpendicular line intersecting the threads–to prevent loosening during recoil.
Identify gas-related components if present. Piston rods or gas blocks manifest as cylindrical protrusions branching from the barrel, often with a drilled port aligning with a corresponding hole in the barrel wall. Blueprints may show a thin tube (gas tube) extending rearward, usually connecting to an operating rod or carrier. Look for arrows or flow indicators near these ports, which denote pressurized gas direction and help differentiate them from ejection ports or cleaning access points.
Examine the muzzle end for devices like choke tubes, compensators, or front sights. These attachments appear as concentric rings or flared shapes with internal threads, sometimes accompanied by dimensional labels (e.g., “IM” for improved modified choke). If the barrel includes a magazine tube, it will run parallel beneath, shown as a hollow cylinder with mounting brackets. Compare the barrel’s contour lines against the receiver’s outline–any asymmetry or angled cuts typically indicate rails for mounting optics or sling swivels.
Verifying Fit and Function Through Schematic Annotations
Cross-reference barrel measurements with the parts list. Blueprints often include tolerances (e.g., “+/- 0.005”) near critical mating surfaces, such as the chamber’s throat or the muzzle’s crown. These values dictate whether components require precise fitting or can accommodate minor deviations. If the barrel assembly includes interchangeable chokes or rifling sleeves, schematics may depict them as modular segments with overlapping lines, signifying optional configurations.
Finally, note symbols indicating surface treatments or coatings. Dashed boxes around the barrel’s exterior frequently denote parkerizing, bluing, or chrome lining, while internal bore coatings might be labeled “nitride” or “electroless nickel.” These details affect maintenance procedures and wear rates, so isolate them from cosmetic markings like logos or serial numbers, which appear as text or engravings without functional purpose. Prioritize parts with clearances affecting cycling–excessive friction or improper headspace often stems from overlooked dimensional callouts in these areas.
Step-by-Step Disassembly Using Blueprint References
Secure the firearm’s action rod with a vise or padded clamp to prevent shifting. Align the bolt release lever with the corresponding notch on the receiver’s right side–marked B-12 on technical drawings–to disengage the bolt. Slide the action bar assembly forward while depressing the shell stop lever (reference C-5 on exploded views) to release it. Rotate the carrier upward until the ejector (part E-7) clears the receiver rails; apply gentle pressure to avoid damaging the retainer spring.
- Remove the forearm by unscrewing the magazine cap counterclockwise–use a 5/16″ socket for torque consistency. Inspect the recoil spring for deformation; replace if compression exceeds 0.12″ beyond OEM specs.
- Detach the trigger guard by driving out the two cross pins (T-3 and T-4) with a brass drift punch. Note the hammer spring orientation (curved side faces rearward).
- Separate the barrel from the receiver by loosening the two vertical screws (F-9)–mark their positions relative to threads for reassembly. Clean carbon buildup from the chamber using a bronze brush and solvent; verify headspace with a GO/NO-GO gauge.
- Disassemble the bolt by removing the firing pin retaining screw (D-2). Rotate the extractor (D-8) 90° counterclockwise to release; store components in labeled bags avoiding magnetized surfaces.