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My Students often ask for suggestions about what AR Tools, Gauges, and Jigs they should buy. When I am asked this question its quite difficult for me to narrow down or compartmentalize a list due to the vast collection I have amassed. I promise my reluctance is not because I don’t want to help, it’s just a difficult task.

I try to buy every AR Tool, Gauge, and Jig available on the Civilian Market. I also collect U.S. Government M4/M16 Tools and Gauges. USGI Gauges and Tools are somewhat rare, very expensive, and collectible. My list will include alternatives to USGI options.

If certain Tools, Jigs, or Gauges are not available on a commercial market, I make them. I do this because having a variety allows me to select the best tools for certain jobs. My Students also get to use, hammer on, and wrench on the tools, so I get to see how well they hold up. Students can mess up a cheap tool right quick.

So here it goes. Remember, this list is geared towards the AR but many of these items can be used to service your other firearms. If I dont suggest something you own, please don’t take offense. This list is a guideline, not the The Good Book. There will be 4 levels:


I will add part #’s when time permits, I’ll do my best to answer any questions.

Basic List

In my opinion these are the basic items for inspection, maintenance, and minor upgrades.
-Brownells Screwdriver (Best) or Wheeler Gunsmith Screwdriver Set (Good)
The Brownells has a lifetime warranty which means if you break a bit, Brownells will replace it with no questions asked. Using Gunsmith Bits are a MUST if you don’t want to hack up you AR, or your other firearms.
-SAE & Metric Socket Set
-Inch Pound Torque Wrench
I like the Wheeler FAT Wrench (Non Digital). The best prices are usually on Amazon. It does forward and reverse torque and clicks/breaks when it reaches the setting. These are great for mounting Rails, Optics, and Gas Key Screws. I own 5 of these and they have held up at my Work Bench and in Classes. Borka and Fix it Sticks are good alternatives, but Wheeler is still my favorite.
-Cheap Steel & Brass 17pc Punch Set
You can get these from Amazon. The kits come with a Spring Loaded Center Punch which can be used for Castle Nut Staking, or “Field Staking” the top of the Carrier Key.
-Needle Nose Plier Set
-Tape Measure
For measuring Buffer Springs.
-.080 Weed Eater Line
-4 to 8 Ounce Ball Peen Hammer
You don’t want a roofing hammer or a claw hammer. A 4 Ounce Ball Peen is my favorite.
-Harbor Freight Rubber Mallet
Great for moving stubborn parts without damaging the material or finish.
-Harbor Freight Plastic Dead Blow Hammer
Great for moving stubborn parts without damaging the material or finish.
-Small Carbon Steel Washer
For checking parts for Magnetism.
-Digital or Analog Calipers
These are for basic checking of parts and for doing a crude a Firing Pin Protrusion check. You can buy a budget models but you can’t always trust them. In my opinion, it’s better to have a Harbor Freight Caliper than nothing, but if you can afford it a good Mitutoyo will give a lifetime of reliable service.
-1.4646 Forster 5.56 GO Headspace Gauge (Brownells)
-Feeler Gauge Set
-Obsidian Arms AR15 Punch Set
-Little Crow Gunworks Bolt Catch Tool
-Brownells Magazine Catch Install Tool
-Brownells Chamber Reflector Tool
-Starrett 117c (Best) or Mayhew 5/32×4 1/2 punch (Good)
These are for staking the Castle Nut if you don’t like using to use Spring Loaded Center Punch
-Pivot Pin Install Tool
You can use an Exacto Knife, Magnet, ¼” Clevis Pin & Punch, Real Avid Tool, or other specialized Tools made for this job. The Real Avid is one of the easiest to use and cost effective.
-M-Guns Gas Tube Bender
-Brownells Gas Tube Wrench/Vise
-Snap Ring Pliers
-Geissele Hammer & Trigger Install Pin Tool
This helps install the AR FCG, but can be used to Oil or Abrasive Lap the bores in an AR Lower Receiver if they are too small.
-AR General Purpose Brush
-Iosso AR Nylon Brush Set
I don’t use bronze or stainless brushes for firearms.
-Rapid Rod (Best) or Steel USGI Sectioned Cleaning Rod (Good)
These are not for regular cleaning. They are great for cleaning in the field and for dislodging a stuck casing.
-One Piece Cleaning Rod and AR Upper Receiver Bore Guide
-Optics Cleaning Kit
-Basic Chemicals/Solvents
Aeroshell 64 (Barrel Nuts and Castle Nuts)
Rocksett or Loctite 271/272
Blue Stick Loctite (NOT the liquid type)
Vibratite VC3
Cold Blue (Steel Touch-up)
Aluminum Black (Aluminum Touch-up)
Synthetic Grease (Assembly Lube)
Kroil Oil (Seized Fasteners)
Steel Wool
Loctite 620 or Permatex Indian Gasket Shellac (Barrel Bedding and for Carrier/Gas Key Installs)
Bore Cleaner (I like Wipe Out Products)
Birchwood Casey Barricade (Great for external wipe downs)

Intermediate List

In my opinion, this is the bare MINIMUM for building and tearing down an AR.
-A SOLID Workbench
You can buy small Work Bench from Lowe’s, Home Depot, and Harbor Freight, but most are very light, have very light/weak frames, and thin work surfaces. Some people are forced to use their kitchen countertops due to limited space or budget. If you mount a Vise to a flimsy or unstable Work Bench it will often move when you try to torque on things, or if you try to remove things like taper pins. If you want a good Workbench you can get a great one for $200.00 at Walmart/Sam’s Club. Their Work Benches are named Seville Classic. They have 2″ Wood tops and are heavy. I have 5 in my Shop/Classroom and they are indestructible and they have a few sizes for those with limited space.
-4″ to 6″ Vise.
You should bolt your Vise to your Workbench and avoid clamp-on arrangements. You can get by with just a Harbor Freight Vise, but it may not last.
A Vise is a must for Installing/Removing a Barrel/Rail System, Installing/Removing a Receiver Extension, or Installing/Removing a Muzzle Device. I use the 4.5″ Yost 445 Vises from Amazon for my Shop/Classroom Work Benches and have held up great.
Yes, people can do the above without a Vise and Work Bench, but in my experience, you’re not going to properly torque things down, or do clean work without a SOLID Workbench and Vise.
-Vise Pads
You don’t want to grab a gun part in a Vise without Vise Pads. There are many options for this, but most are not great. In my opinion the best ones are made at home. I use Trex Decking material and Leather. The alternative is 4.5″ magnetic rubber Vise Blocks from Amazon.
-½” Foot Pound Clicker Torque Wrench
A Harbor Freight model will work here but not for a lifetime of uses. Do your research and buy the best one you can afford. The beam types will work, but they are not easy to deal with when cranking on an AR. Torque Wrenches remove the human element from a job and create consistency in the work. I can build an AR without one, but I still use a Torque Wrench.
-Tapco Multi Tool Green Armorers Wrench
Yes, Tapco. My second choice is the Magpul Armorer’s Wrench. It’s the most versatile wrench when it comes to aftermarket parts like barrel nuts, muzzle devices, and receiver extensions. It isn’t as comfortable to use as others, but it is a great wrench with a great warranty.
-Geissele Reaction Block or Kley Zion Buffer Tube Jig
Which one you choose depends on what you will be working on. The Geissele ONLY works on Milspec Receiver Extensions. The Kley Zion works on Milspec AND Commercial Receiver Extensions. So if you only own Milspec Receiver Extensions, the Geissele is best. If you will be working on other people’s AR’s , you have no control on what they will bring you and I guarantee there will be Commercial Receiver Extensions you have to contend with.
-Wood Block
Good for supporting Barrel when using a Reaction Rod type tool, and good for hammering on FSB Taper Pins.
-Leather Remnants, Brass Sheets, and Lead Sheets.
These are good for backing items you don’t want to damage. Different material are good for different purposes.
-Magpul BEV Block
The BEV Block does work as a Barrel Install/Removal Tool and a Magazine Well Block. If you only need a Magazine Well Block then a NoMar Magazine Block will be a cheaper alternative.
-Harbor Freight Diamond File Set
Sometimes you need a file a part to fit and these cheap files work very well. If you are not patient, don’t have a steady hands, or a precise eye, then DON’T buy files. Remember to always file the cheaper part.
-Mark Brown Customs Gas Tube Gauge
-Schuster Sling Staking Tool
-2# Hammer
For removing Taper Pins
-1/2″ Tip Punch
For removing Taper Pins
-Propane Torch
For removing stuck/seized parts. MAP Gas is better but propane will work. Don’t get items cherry red.
-Gas Block Geanie, HB Industries Gas Block Alignment Pins, or Pasta
All of these are for aligning gas blocks to the gas port.
-Canned Air
Turn it upside down and shoot liquid on parts you want to take apart or put together. Sometimes freezing a part is better than heat.
-1.4636 Forster .223 GO Headspace Gauge
-1.4736 Brownells 5.56 Field Headspace Gauge
This is made by Forster
-NoMar Rail Blocks or YHM Rail Blocks
These help alignment of Handguard Rails to the Upper Receiver when you are installing screws or tightening clamping bolts.
-½” Drive 2’+ Breaker Bar
For removing stuck Barrel Nuts.
-KNS Hammer Cage Tool
Good for people with large fingers, or those with arthritis.
-Digital Depth/Anvil Gauge
For quick and accurate Firing Pin Protrusion measurement.
-Brownells Barrel Nut Alignment Rod
This is great to check for barrel nut alignment. If used in a stripped upper it will show you if your has key is not true.
-Midwest URR
I don’t recommend the Geissele Reaction Rod or the Kley Zion Clone. If you use a Torque Wrench, the Reaction Rod type devices are fine for Upper Receiver assembly, but if you plan on tearing down AR Uppers or changing Rails you really don’t want the Reaction Rod. The Reaction Rod is NOT good for trying to remove seized or over torqued Barrel Nuts. Think about how the Reaction Rod works. It holds the Barrel in a static position but does NOT lock the Upper Receiver in place. If you have a stuck/seized Barrel Nut, the Upper Receiver will try to spin with the Barrel Nut. What keeps the Upper Receiver from spinning? The Barrel Index Pin does, and it will break off if you add too much force. Seen this countless times. This is why the Midwest URR is best tool for the job, it has a sail that locks into the charging handle slot, and teeth that lock into the barrel extension. These two features prevents the Upper Receiver and Barrel Extension from spinning. The Midwest URR is a gauge of sorts as well. If your upper is twisted, or the Barrel Extension is not timed properly, the tool won’t go into the upper properly. I have a video showing this issue from a few weeks ago. Clamshell Upper Receiver Blocks are great for removing a stuck/seized Barrel Nut, but the Clamshell Blocks won’t work on some billet Uppers Receivers, and you can’t use heat on the Barrel Nut without melting the Clamshell Blocks.
-PRI Gas Block Punch Block
Great for installing Gas Tubes in a Low Profile Gas Block
-Wheeler Bench Block
Works great for installing Roll Pins in the Trigger Guard, Charging Handle, and Bolt Catch. It can be used for removing FSB Taper Pins, but I don’t use it for that feature.
-Sinclair Bolt Vise
For removing Bolt Ejector and Reinstalling it. You can do this without a Bolt Vise but this tool simplifies the job.
-Sharpening Stone
For resurfacing/decking a Gas Key
-M-Guns MOACKS Staking Jig
There is no other good option. I have tried them all. I suggest you avoid using striking tools to stake from the side of the Gas Key. Doing so will stress the Gas Key Screws.
-Bondhus Metric & SAE Ball Tip Allen Drivers
-Blue Point Strap Wrenches
Best strap wrenches I have used.
-Timney Trigger Pull Gauge
-No-Mar or Brownells Hammer Drop/Dryfire Block
-.061-.250 Pin Gauge Set
That set will allow you to check the following:
Barrel Gas Ports, GO Spec for Bolt Firing Pin Hole (NO GO .070 requires a Taper Plug Pin Gage), GO Spec for Lower Receiver Hammer & Trigger Holes (NO GO.163 requires a Taper Plug Pin Gage), FCG Hammer & Trigger Holes, Carrier Key Bore, Cam Pin Bore, FSB/Gas Block Gas Tube Bore, GO Spec for Pivot & Takedown Bores (My NO GO Spec is .253, so that is outside the range of this Set).
You can’t do the following with this set:
Gas Block/FSB Barrel Journal Bore, and Bolt Carrier 3 Bore.
-Selector/Safety Bore

Professional List

-Brownells Apron or similar Apron
A good Apron is a must for a professional Armorer or Gunsmith.
-Hawkeye Borescope
This is for Barrel Inspection, Bolt Carrier Inspection, Suppressor and Muzzle Device Inspection, but most of all it’s great for aligning Gas Blocks. The Lyman Borescope is MUCH more affordable, but it’s not as clear and may not work well for Gas Block Alignment. I will be testing a very cheap alternative soon and if it works, I’ll update this post.
-Saturn Barrel Blocks
They grab like no other Barrel Blocks.
-.625 & .750 SLR or BRDE Barrel Dimple Jig
For Dimpling Barrels for Gas Block Set Screws. I recommend a drill bit collar and carbide bits to use these Jigs. A Drill Press or Mill is best but you can use a Hand Drill.
-Carbide Drill Bits for Dimple Jig
-PTG or Brownells Lapping Tool
Get training before using this tool.
-Brownells Magazine Lip Gauge
-Bushnell bore sighter/collimator
-Thread Checker
Helps you determine threat types in case you have to go to the hardware store for a fastener.
-Sweeny Site A Line Spud
Used with the Bushnell Collimator or a Collimator Jack from Brownells
-Site Lite Bore Sight Laser
-Arisaka Leveling Kit
-CKT Level
-Badger Ordnance Dead Level
-.625/.750 Flex Hones
For deburring FSB and Gas Block bores
-Rotary Tool
Get training or practice A LOT before using this tool. Ones with a flex shaft are easier to use.
-Feed Ramp Rework Polish Kit:
-1/4″ Bullet Tip Stone (For cutting the Barrel Extension Ramps ONLY), #8 Cratex Bullet Coarse (Brownells Part # 190-025-081), #8 Cratex Bullet Fine (Brownells Part # 190-025-083), #4 Pointed Mandrel for Cratex Tips (Brownells Part # 190-001-004), 1/4″ x 3/8″ x 1/8′ Felt Bob (Brownells Part # 839-500-025), 555 Polish (For Felt Bob – Brownells Part # 080-555-001)
-LCGW Trigger Guard Press
-M-Guns Throat Gauge
-PTG Muzzle Erosion Gauge
-Merchant/Brownells Throat Erosion Gauge
-PTG Barrel Straightness Gauge
-Schuster Thread Concentric Gauge
Checking for Thread to Bore Run-Out
-Geissele or Surefire Suppressor Alignment Rods
-Granite Slab
For checking for bent or untrue items.
-USGI Barrel Nut Wrench with 3 Prong F.H. Tool
-YHM Lock Ring Wrench/Tool
-DPMS Armorers Tool
Needed for older Free Float Tubes and some Integrally Suppressed AR’s.
-Broken Shell Extractor or Cerro Safe
-Sight Adjustment Tool
-Law Tactical Tool
-AAC 3 Prong Flash Hider Tool
-Schuster Barrel Nut Alignment Rod
-Iron Pipe
Breaker Bar Extension
-Crows Foot Wrench Set
-Damaged Screw Extractors
-Two 3/32″ x 12″ Drill Rods
For Muzzle Device Alignment
-Geissele Gas Tube Punch Set
-PTG or Brownells Upper Receiver Lapping Tool
Proper training is necessary to use this tool.
-Jewelers Screwdriver Cobalt 759897
-USGI Firing Pin Hole Taper Plug Gage (RARE) or School of the American Rifle Firing Pin Hole Taper Plug Gauge
-Lower Receiver Hammer & Trigger Bore Taper Plug Gauge
-USGI Lower Receiver Hammer & Trigger Bore Taper Plug Gauge (RARE) or School of the American Rifle Lower Receiver Hammer & Trigger Bore Taper Plug Gauge

Insane List

-Taps, Dies, & Handles
(Taps & Dies 1/4-28, 10-32, 8-32, 1 3/16-16, 1/2-28, 1/2-36, 5/8-24, 1 1/4-18)
-Black River Tactical Gas Block Insert Tap Set
-Tap Magic Aluminum
-Tap Magic Standard
-M-Guns Throat Reamer
-4-40 Tap
For Takedown Set Screw Modification
-NRA Trigger Weight Kit
-Stainless Shim Stock in .0005 and .0010
Barrel Extension Shimming/Bedding
-Number Drill Bit Set
-Campfire Wood Skewers
Put them in the bore when you have to open a Gas Port. When you see wood chips you know to stop.
-Drill Press/Mill
-Gunsmith Lathe
-Daves Metal Works Upper Receiver Fixture
For facing upper receivers in Lathe.
-Cut Away AR15
-Barrel Extension Install/Removal Tool & Barrel Vise
-Large Frame AR Tools
-Proprietary KAC AR Tools
-Additional AR Gauges (Gauges: Headspace, Barrel Straightness, Muzzle Erosion, Throat Erosion, Suppressor Alignment Gauge) (Calibers: .300 Blackout, .308, 7.62×51 NATO, 6.5 CM, 7.62×39, 6.5 Grendel, 6.8SPC, 9mm Luger, .458 SOCOM, .22 L.R.)
-Proprietary Barrel Nut Wrenches
-Ruby Stones
FCG Stoning and Deburring
-Brownells Castle Nut Tool
Good for old Style Castle Nuts & KAC Castle Nuts
-Bownells Impact Driver
For seized Fasteners
-Present Arms Armorers Block Kit
Great for prefectly timed Receiver Extensions
-FCD Castle Nut Wrench
Needed for Present Arms Castle Nut work.
-.251-.500 Pin Gauge Set
-.501-.625 Pin Gauge Set
For measuring Takedown/Pivot NO GO, Bolt Carrier 3 Bore, Selector/Safety Bore
You can’t do the following with this set:
Block Barrel Journal Bore for the FSB/Gas Block
-Forster 11 Piece .223 Match Headspace Gage Set or PTG 5.56 11 Piece Set
-Mitutoyo 0-1″ Micrometer
-BRDE Universal Gas Plick Pin/Drill Jig
-Toaster Oven
For Thermal Fit items
-Bead Blasting Cabinet
-1 3/16-16 UN 2B & 3B GO (Both have the same dimensions) Thread Plug Gauge
For Castle Nut and Lower Receiver
-1 3/16-16 UN 3B NO GO Thread Plug Gauge
For Castle Nut and Lower Receiver
-1 3/16-16 UN 3B NO GO Thread Plug Gauge
For Castle Nut and Lower Receiver
-1 3/16-16 UN 2A GO & NO GO Thread Ring Gauges
For Receiver Extension
-1 3/16-16 UN 3A GO & NO GO Thread Ring Gauges
For Receiver Extension
-USGI 1 3/16-16 Thread Comparator Gage
-Parts Washer
-Bucket Heater
For Parts Washer
-Simple Green Precision (NOT regular Simple Green)
For Parts Washer
-Ultrasonic Cleaner
Suppressor Baffles and BCG Cleaning
-Air Compressor
-Buffing Wheel Station
-Brass Crown Repair Laps
-USGI Magazine Well Plug Gauge # 8439649
-USGI/USMC Lower Receiver Pivot Recess Gage

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