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Work order — Smith & Wesson M&P15
Taking the firearm apart for a job such as refinishing, and putting it back together to specification. Generated from the Pew-Takedown entry last updated 2026-10-29. Confidence: high.
| Work order # | |
|---|---|
| Customer | |
| Model on the bench | |
| Serial number | |
| Finish / colour | |
| Received | |
| Technician |
- Smith & Wesson limits owner disassembly: Field strip: upper and lower receivers separated, bolt carrier assembly and charging handle out; handguard removal described but noted as not generally necessary.
Shop difficulty: Tier 2 of 3
A mil-spec-pattern AR-15, so it has the same full-strip traps as the AR-556: captive pivot and takedown detents, the buffer retainer, the selector detent, roll pins, and a hammer spring that only goes one way. 131 parts (stand-in: Colt AR15-A2 Sporter (civilian semi-automatic AR-15, same mil-spec AR-15 receiver/bolt/fire-control pattern as the M&P15) per the Gun Digest exploded drawing legend, keys 1-131, complete rif). Pew-Takedown's rating, not the manufacturer's.
Bench time: strip ~45 min, rebuild ~70 min (estimate). Actual: strip ______ rebuild ______
Special tools:
- AR armorer's wrench — Castle nut, muzzle device
- vise blocks — Receivers
- roll pin punches — Bolt catch, trigger guard, gas block pins
- pivot pin detent tool — Front pivot pin detent
Watch for:
- The front pivot-pin detent and spring launch during install without a pivot-pin tool. (reassembly; ITS Tactical)
- A reversed hammer spring looks seated but does not detent the trigger pin. (reassembly; Gun Tests)
- S&W stops the owner at the extractor. Anything further is factory or gunsmith work, so there is no maker procedure for the lower. (both; Smith & Wesson)
1. Clear and make safe
- Point the muzzle in a safe direction and keep your finger off the trigger.
- Press the magazine release and remove the magazine.
- Pull the charging handle fully to the rear and lock the bolt back with the bolt catch.
- Visually inspect the chamber and magazine well, then physically feel the chamber to confirm it is empty.
Warning: Check the magazine well as well as the chamber — a round can hang up there. - If the hammer is cocked, place the selector on SAFE.
- Remove all live ammunition from the work area.
2. Disassemble
Manufacturer's video: Field Stripping Your Modern Sporting Rifle (Smith & Wesson)
https://www.youtube.com/watch?v=zo-Le55Osqw
Field Strip
- Complete the Clear and Make Safe procedure and release the bolt forward.
- Push the rear takedown pin from the left side until it stops in its captured position.
Tip: If tight, tap it with a punch or a case rim rather than levering it. - Pivot the upper receiver forward on the front pivot pin.
- Push the front pivot pin out to its captured position and separate the upper from the lower receiver.
- Pull the charging handle partway rearward and withdraw the bolt carrier group.
- Pull the charging handle down and out of its channel.
Warning: The charging handle comes out after the carrier, never before.
3. Refinish
The components the procedures above separate. Coating, masking and cure are outside this database; follow your coating system's instructions. A part the manufacturer marks "factory fit" should not be swapped or reworked.
| Component separated | Out | Coated | Back in |
|---|---|---|---|
| Upper receiver assembly | |||
| Bolt carrier group | |||
| Charging handle |
| Component | Material | Factory finish | Source |
|---|---|---|---|
| Receiver (upper/lower) M&P15 Sport II, 16in, SKU 10202 | ALUMINUM | — | [5] |
| Barrel M&P15 Sport II, 16in, SKU 10202 | 4140 CM | — | [5] |
| Whole firearm M&P15 Sport II, 16in, SKU 10202 | — | BLACK | [5] |
| Grips M&P15 Sport II, 16in, SKU 10202 | POLYMER | — | [5] |
Labelled parts in the manufacturer's documents:
- Model and features identification (labelled photos of the rifle) — Safety & Instruction Manual for Centerfire Semi-Automatic Rifles including Volunteer Series & Sport Series (p/n 3015611, REV S&W_M&P_CF_MSR_REV_022724, © 2024), linked from smith-wesson.com/products/mp-15-sport-iii, p. 12–15
https://smith-wesson.canto.com/direct/document/s9hki7flkd0ar8802osm6p5j75/l-npJQUqV1KM75UlvNhw1q3siAA/original?content-type=application%2Fpdf#page=12
4. Reassemble
Reassembly
- Insert the bolt into the carrier with the extractor oriented toward the ejection port side.
- Push the bolt fully into the carrier, drop the cam pin into its hole, and rotate it 90 degrees.
Warning: If the cam pin is not rotated, the firing pin will not seat. Never force the firing pin. - Drop the firing pin into the rear of the carrier, tail first, and let it seat fully.
- Install the firing pin retaining pin. If it will not go in, the cam pin is missing or not rotated.
Warning: This is the design’s built-in check. Do not defeat it. - Insert the charging handle into its channel and push it partway forward.
- Insert the bolt carrier group into the charging handle’s track and slide both fully home.
- Mate the upper to the lower, press the front pivot pin home, close the receivers, and press the rear takedown pin home.
- Charge the rifle and perform the function check.
5. Torque
| Fastener | Specification | Sequence | Source | Applied | Init. |
|---|---|---|---|---|---|
| One-piece free-floating forend/rail screws (3), 5/32˝ driver S&W M&P Sport series and Volunteer series centerfire rifles with a one-piece aluminum free-floating forend (e.g. M&P15 Sport III), if so-equipped |
45–50 in-lb 5.1–5.6 N·m · 3.7–4.2 ft-lb |
Check that these (3) forend screws are secure (FIGURE 68). | [3] p. 33 | ||
| Forend/rail screws (3), 5/32˝ driver S&W California Compliant Model centerfire semi-automatic rifle (M&P15 Sport III CA compliant) |
45–50 in-lb 5.1–5.6 N·m · 3.7–4.2 ft-lb |
Check that these (3) forend screws are secure (FIGURE 118). | [4] p. 48 | ||
| M-LOK accessory screws: polymer accessories to metal handguards S&W M&P15 / M&P Sport and Volunteer series rifles with M-LOK handguards (M-LOK accessory rails and accessories) |
15 in-lb 1.7 N·m · 1.2 ft-lb |
Thread the T-nuts onto the (nylon-patched) screws, insert and 'bias' the accessory toward the front of the slot, then 'tighten all fasteners to the recommended torque spec'; confirm the T-nut rotates 90° into the locked position. Source: 'The installation torque values are not minimums, they are recommended limits. The nylon patch compound (thread lock) may slightly affect the torque reading if using an in/lb torque wrench.' Threadlocker: Screws have a nylon patch; if worn, restore with Rocksett or Loctite blue thread-locker stick |
[3] p. 57 | ||
| M-LOK accessory screws: polymer or metal accessories to polymer handguards S&W M&P15 / M&P Sport and Volunteer series rifles with M-LOK handguards (M-LOK accessory rails and accessories) |
15 in-lb 1.7 N·m · 1.2 ft-lb |
Thread the T-nuts onto the (nylon-patched) screws, insert and 'bias' the accessory toward the front of the slot, then 'tighten all fasteners to the recommended torque spec'; confirm the T-nut rotates 90° into the locked position. Source: 'The installation torque values are not minimums, they are recommended limits. The nylon patch compound (thread lock) may slightly affect the torque reading if using an in/lb torque wrench.' Threadlocker: Screws have a nylon patch; if worn, restore with Rocksett or Loctite blue thread-locker stick |
[3] p. 57 | ||
| M-LOK accessory screws: metal accessories to metal handguards S&W M&P15 / M&P Sport and Volunteer series rifles with M-LOK handguards (M-LOK accessory rails and accessories) |
35 in-lb 4 N·m · 2.9 ft-lb |
Thread the T-nuts onto the (nylon-patched) screws, insert and 'bias' the accessory toward the front of the slot, then 'tighten all fasteners to the recommended torque spec'; confirm the T-nut rotates 90° into the locked position. Source: 'The installation torque values are not minimums, they are recommended limits. The nylon patch compound (thread lock) may slightly affect the torque reading if using an in/lb torque wrench.' Threadlocker: Screws have a nylon patch; if worn, restore with Rocksett or Loctite blue thread-locker stick |
[3] p. 57 |
Notes: S&W says of the M-LOK values that they "are not minimums, they are recommended limits" — treat them as the most to apply, not a target to reach. The forend/rail screw value applies only to rifles fitted with S&W's one-piece free-floating forend.
Fit or check on rebuild
- Hammer spring orientation and pins flush — A reversed spring will not detent the trigger pin.
- Function check (safety, trigger reset, feeding, extraction) — Standard after any detail strip. No single source.
- Re-zero sights or scope — Sights and optics come off for coating, and point of impact must be re-confirmed. This is a standard check, so no source.
6. Function check
- Verify the rifle is unloaded with no magazine inserted before each step.
- Charge the rifle to cock the hammer, place the selector on SAFE, and press the trigger. The hammer must not fall.
- Move the selector to SEMI and press the trigger. The hammer should fall.
- Hold the trigger to the rear, charge the rifle, then release the trigger slowly and listen for the disconnector to release the hammer to the trigger.
- Press the trigger again. The hammer should fall.
- Insert an empty magazine, charge the rifle, and confirm the bolt locks back.
If any check fails, the firearm is not safe to fire. Stop and see a licensed gunsmith.
Sources
- TM 9-1005-319-10: Rifle, 5.56mm, M16A2/M4 Carbine — U.S. Department of the Army primary
- Smith & Wesson M&P15 Owner’s Manual — Smith & Wesson primary
- Safety & Instruction Manual for Centerfire Semi-Automatic Rifles including Volunteer Series & Sport Series (p/n 3015611, REV S&W_M&P_CF_MSR_REV_022724, © 2024), linked from smith-wesson.com/products/mp-15-sport-iii — Smith & Wesson primary
https://smith-wesson.canto.com/direct/document/s9hki7flkd0ar8802osm6p5j75/l-npJQUqV1KM75UlvNhw1q3siAA/original?content-type=application%2Fpdf - Safety & Instruction Manual for California Compliant Model Centerfire Semi-Automatic Rifle (© 2026), linked from smith-wesson.com/products/mp-15-sport-iii — Smith & Wesson primary
https://smith-wesson.canto.com/direct/document/3mde9sn0ct7ahcmuhjjkl7dt47/uQBnHdgJknuPT3BBklTqKtQQ6yM/original?content-type=application%2Fpdf - Smith & Wesson M&P15 Sport II — product specifications, SKU 10202 — Smith & Wesson Brands, Inc. primary
https://www.smith-wesson.com/product/m-p-15-sport-ii - Virtual Patent Marking | Smith & Wesson — Smith & Wesson primary
https://www.smith-wesson.com/company/virtual-patent-marking - DIY AR-15 Build: Pivot Pin Installation — ITS Tactical secondary
https://www.itstactical.com/?p=10638 - (Gunsmithing the AR-15 #2) The 30-Second AR Check — Gun Tests secondary
https://www.gun-tests.com/?p=26007 - The Gun Digest Book of Exploded Gun Drawings (975 isometric views) — Colt 'AR15-A2 Sporter Autoloading Rifle' — Gun Digest Books / Krause Publications (scan on archive.org) secondary
https://archive.org/download/the-book-of-exploded-gun-drawings-975-isometric-views/The%20Book%20of%20Exploded%20Gun%20Drawings%20-%20975%20Isometric%20Views.pdf
| Reassembled and function-checked by | Date |
|---|
Educational guide only. Some information comes from non-authoritative sources. Always consult your manufacturer's manual and a licensed gunsmith. Verify your firearm is unloaded before every procedure. Full disclaimer: https://github.com/Fundamental-build-LLC/Pew-Takedown
Legal notice: this material is third-party information compiled from sources of varying reliability and is provided for general informational and educational purposes only. It is not gunsmithing, technical, safety or legal advice, it is not verified or endorsed by any manufacturer, and it must not be taken as fact. Any work on a firearm beyond the routine field stripping described in its own owner's manual should be performed only by a licensed and insured gunsmith. You use this material entirely at your own risk. Fundamental Build LLC and the project's contributors make no warranty of any kind and accept no liability for death, injury, damage or loss arising from its use. Full terms: LEGAL.md.