AR-15 Torque Specs: Complete Reference Chart
Every fastener on an AR-15 has a torque value. This interactive reference covers barrel assembly, upper and lower receiver, handguard, and optics. Use the table view to search and sort, or switch to the diagram view to explore torque specs visually.
17 of 17 specs
| Fastener | Thread Locker | Tool | Notes | ||||
|---|---|---|---|---|---|---|---|
Barrel Nut | Barrel Assembly | Barrel nut onto upper receiver | 55 | 660 | None | Armorer wrench, torque wrench (3/8" drive) | Range is 30 to 80 ft-lbs. Start at 30 ft-lbs, then torque up in stages to align the gas tube hole with the receiver. NEVER use thread locker on barrel nut threads. Lube threads with Aeroshell 33MS or equivalent. Source: TM 9-1005-319-23&P |
Muzzle Device | Barrel Assembly | Muzzle device onto barrel | 17 | 204 | Rocksett | Armorer wrench, torque wrench | Range is 15 to 20 ft-lbs. Use a crush washer OR Rocksett, not both. Time the device to 12 o'clock. For pinned and welded configurations, complete weld before final torque check. Source: TM 9-1005-319-23&P |
Gas Block Set Screws | Barrel Assembly | Set screws into gas block | n/a | 30 | Red Loctite 262/263 | 1/16" hex key, inch-pound torque wrench | Range is 25 to 35 in-lbs. Red Loctite 262 OR Rocksett required to prevent loosening under heat. Verify gas port alignment before final torque. Source: Manufacturer spec (BCM, Geissele, Daniel Defense) |
Gas Block Clamp Screws | Barrel Assembly | Clamp-on gas block screws | n/a | 30 | Blue Loctite 242/243 | 9/64" hex key, inch-pound torque wrench | Range is 25 to 35 in-lbs. Alternate between screws in multiple passes to seat evenly against the barrel. Source: Manufacturer spec (Geissele, SLR Rifleworks) |
Handguard Mounting Screws | Handguard | Free-float handguard to barrel nut | n/a | 30 | Blue Loctite 242/243 | Hex key (manufacturer specific), inch-pound torque wrench | Range is typically 25 to 35 in-lbs. Check your specific handguard manufacturer's instructions. Tighten in a cross pattern. Source: Manufacturer spec |
M-LOK Screws | Handguard | M-LOK accessory T-nut screws | n/a | 20 | None | T15 Torx, inch-pound torque wrench | Range is 15 to 25 in-lbs per the Magpul M-LOK spec. Do not exceed 35 in-lbs or T-nut damage will occur. Source: Magpul M-LOK Spec |
Bipod Mount | Handguard | Bipod adapter mounting screw | n/a | 45 | Blue Loctite 242/243 | Hex key, inch-pound torque wrench | Varies by manufacturer. Harris bipod spec is 40 to 50 in-lbs. Check your specific bipod manufacturer's instructions. Source: Manufacturer spec (Harris, Atlas, Magpul) |
Castle Nut | Lower Receiver | Castle nut on receiver extension | 38 | 456 | None | Castle nut wrench, torque wrench, staking tool | Range is 35 to 40 ft-lbs. After torquing, STAKE the castle nut into the receiver end plate in two places. Unstaked castle nuts back off and can cause the buffer tube to unscrew during fire. Source: TM 9-1005-319-23&P |
Pistol Grip Screw | Lower Receiver | Grip screw into lower receiver | n/a | 50 | Blue Loctite 242/243 | 1/4" hex key, inch-pound torque wrench | Range is 40 to 60 in-lbs. Do not overtighten or the grip body will crack. Blue Loctite optional but recommended. Source: TM 9-1005-319-23&P |
Buffer Tube | Lower Receiver | Receiver extension into lower | n/a | n/a | None | Armorer wrench | No published torque value. Thread in by hand until it bottoms out on the castle nut and end plate, then snug 1/8 turn. Final retention comes from the castle nut, not the buffer tube. Source: TM 9-1005-319-23&P |
Trigger Guard Roll Pin | Lower Receiver | Roll pin through receiver ears | n/a | n/a | None | Roll pin punch set, support block | Press fit only, no torque spec. Support the receiver ears with a block to prevent breakage while driving the pin. Source: TM 9-1005-319-23&P |
Selector Detent Spring | Lower Receiver | Selector safety detent | n/a | n/a | None | None (captive) | Spring loaded, no torque spec. The pistol grip retains the detent spring. Source: TM 9-1005-319-23&P |
QD Sling Mount | Lower Receiver | QD sling mount body screw | 12 | 144 | Blue Loctite 242/243 | Hex key, torque wrench | Range is 10 to 15 ft-lbs. Spec varies by mount manufacturer (VTAC, Magpul, Ferro Concepts). Source: Manufacturer spec |
Scope Ring Screws | Optics | Scope rings clamping tube | n/a | 20 | None | Hex or Torx bit, inch-pound torque wrench | Range is 15 to 25 in-lbs. Follow per manufacturer spec. Alternate between screws in a cross pattern to seat evenly. Never exceed ring manufacturer torque. Source: Manufacturer spec (Vortex, Badger Ordnance, Nightforce) |
Picatinny Rail Screws | Optics | Rail section mounting screws | n/a | 13 | Blue Loctite 242/243 | T15 Torx, inch-pound torque wrench | Range is 12 to 15 in-lbs. Use blue Loctite to prevent walking under recoil. Source: MIL-STD-1913 |
Optic Mount to Upper | Optics | Optic mount clamp bolts | n/a | 45 | None | Hex or Torx bit, inch-pound torque wrench | Follow the optic manufacturer's torque spec exactly. Common specs: Geissele Super Precision 55 in-lbs, Bobro 65 in-lbs, Scalarworks 35 in-lbs. Source: Manufacturer spec |
Gas Key Screws | Upper Receiver | Gas key to bolt carrier | n/a | 58 | Red Loctite 262/263 | 9/64" hex key, inch-pound torque wrench, staking tool | Range is 35 to 58 in-lbs per TM. Torque BOTH screws, then STAKE properly. Improperly staked gas keys are the #1 cause of short-stroking and catastrophic carrier failure. Source: TM 9-1005-319-23&P |
Rows marked with a red dot require staking after torquing. See safety warnings below.
Critical Safety Warnings
- Gas key staking: After torquing both gas key screws, they must be mechanically staked into the gas key body. An unstaked or improperly staked gas key is the leading cause of short-stroking, screw backout, and catastrophic bolt carrier group failure. Use an MOACKS or equivalent staking tool.
- Castle nut staking: The castle nut on the receiver extension must be staked to the receiver end plate in at least two places. An unstaked castle nut can back off under recoil, allowing the buffer tube to unscrew during fire.
- Barrel nut alignment: The barrel nut must be torqued between 30 and 80 ft-lbs to align the gas tube hole with the upper receiver. NEVER exceed 80 ft-lbs. NEVER use thread locker on barrel nut threads. Always lube the threads with Aeroshell 33MS or equivalent grease.
- Muzzle device timing: For pinned and welded configurations, complete the weld before final torque check. Over-timing by adding torque beyond 20 ft-lbs with a crush washer risks cracking the muzzle device or damaging the barrel shoulder.
- Use a calibrated torque wrench: Click-type torque wrenches lose calibration over time. Verify calibration annually. A miscalibrated wrench is worse than no wrench at all.
Thread Locker Guide
Thread lockers prevent fasteners from loosening under vibration and recoil. Using the wrong type (or any at all, in some cases) will cause failures. Here is when to use each.
Blue Loctite 242/243
Medium strength, removable with hand tools. The default thread locker for most AR-15 fasteners.
- Use on: pistol grip screw, picatinny rail screws, gas block clamp screws, QD sling mounts
- Fully cured at 24 hours
- Removable with standard hand tools at room temperature
Red Loctite 262/263
High strength, requires heat (approximately 500 F) to remove. Use only where permanent retention is required.
- Use on: gas key screws, gas block set screws (set-screw type)
- Do NOT use on anything you want to remove without a torch
- Do NOT use on polymer or painted surfaces
Rocksett
Heat-resistant ceramic compound. Designed for high-temperature applications where Loctite breaks down.
- Use on: muzzle devices, gas block set screws (high-heat alternative)
- Withstands temperatures over 2000 F
- Removable by soaking in warm water for 10 to 30 minutes
Vibra-Tite VC-3
Pre-applied removable thread locker. Alternative to blue Loctite that can be adjusted and retorqued without reapplying.
- Use on: optic mount screws, scope ring screws, accessories that get adjusted
- Stays flexible and can be broken multiple times
- Not a substitute for red Loctite on critical staked fasteners
When NOT to use thread locker
- NEVER on barrel nut threads. The barrel nut needs to rotate during indexing, and thread locker interferes with torque readings and can damage the upper receiver on removal.
- NEVER on castle nut threads. Castle nut retention comes from mechanical staking, not chemical. Thread locker can mask a loose nut.
- Not on muzzle device threads if using a crush washer. The crush washer provides the indexing. Use Rocksett only if you want permanent retention.
- Not inside a receiver where polymer or anodizing is present. Loctite can dissolve some finishes and plastics.
Disclaimer
Torque specifications are sourced from published military technical manuals and manufacturer data. Always follow the specific manufacturer's instructions for your components. Use a calibrated torque wrench. AR15 Outfitters is not responsible for damage or injury resulting from improper assembly. If you are not comfortable performing any of this work, consult a certified armorer.
When to re-torque
Torque values drift with heat cycles, vibration, and disassembly. Check critical fasteners on the schedule below and run a full pass whenever you notice unusual point of impact shift or accessory movement.
- Break-in (first 200 rounds): Re-check scope rings, optic mount, gas block set screws, and castle nut stake after the first range trip.
- Every 1,000 rounds or annually: Re-verify handguard barrel nut seating, muzzle device index, and grip screw.
- After any disassembly: Re-torque with fresh thread locker where called for. Do not re-use old Loctite on fasteners rated for it.
- After extended sustained fire: Hot fasteners can loosen. Let the rifle cool, then re-check gas key screws visually (they should still be staked) and muzzle device.
Need the right tools?
A calibrated torque wrench, armorer wrench, and staking tool are the minimum for safe AR-15 assembly. Find builder-grade tools in our shop.
Most loose or broken fasteners trace back to missed service intervals. Pair these torque values with a round count based maintenance schedule to catch issues early.
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