The Ultimate Firearms Destination for the Gun Lifestyle

AR Armorer Tools

The Right Tool Makes All the Difference

Some would have you think the modern AR-15 is a mystical device and working on one requires an eon of apprenticeship and a degree in mechanical engineering. Not so. All you really need is a willingness to learn by breaking stuff, enough cash to replace those broken parts, and a good set of tools.

We spoke to a handful of armorers to get a feel for the best tools to get you through the most common jobs. Robb Jensen is a commercial armorer with Virginia Arms in Manassas, Virginia, Corporal Sean Dougherty is a SWAT officer and team armorer for Union County Police Department in New Jersey, and Nathan Murr is a prior service Marine and lay armorer who’s leveraged his firearm experience into a career working on government guns and designing his own firearm accessories.

Far and away the most common task performed by our armorers is swapping a G.I. handguard for a free-floating handguard. This is a pretty intense job because it generally involves pulling the barrel and replacing the gas block. Not the simplest of jobs, but one that can be done by anyone with the proper mindset and the right tools.

The second most common job is installing an aftermarket trigger. After that, the array of work includes installing ambidextrous fire selectors, new grips, and new muzzle devices. Some of these jobs are simple, some require taking other components off the gun to complete the primary objective. Building a gun from parts is less common for these guys, and most professional shooters will tell you it takes a lot of experience to choose the correct components to build a reliable and safe Frankengun. That being said, assembling a stripped lower and combining it with a factory-built complete upper receiver is a very popular and viable option for less experienced builders who don’t want to deal with next level headaches such as headspace issues or gas system troubleshooting.

All of our armorers agree that wrenching on your own guns is the best way to learn. Get good, and it won’t be long before you’re installing handguards and triggers for your less mechanically inclined friends. Just be aware that you’re responsible for everything you do to a firearm. There are some things armorers don’t do — and we’re suggesting you steer clear of things like stoning triggers. It’s too easy to bone up a trigger and get someone hurt when a gun decides to dump a mag on its own.

Lastly, before anyone whines about spending money on tools, please realize that none of these tools are necessary for working on an AR. Our intention is to point out tools that make any job faster, easier and, therefore, way more pleasant.

The Basics

Whether building, repairing, or servicing just about any firearm, it’s certain you’ll encounter roll pins and screws. To deal with them effectively, you’ll want at least a set of roll pin punches, a lightweight hammer, and a set of screwdrivers.

A Brownells Roll Pin Punch Set will last dozens or more projects, with individual punches needing replacement when a shaft bends or a tip begins to mushroom. To make life easy, protect your fingers and increase tool life, consider adding a Brownells Roll Pin Holder Set and Roll Pin Starter Kit to your toolbox. A roll pin holder looks like a hollow-ended punch. You drop a pin in the end and it holds it on-axis while you tap it in. Without the holder, you’re left holding the pin with your fingers as you tap it. Roll pin starter punches help get tough pins moving when they require forces that’ll bend longer, thinner roll pin punches. Once the pin is knocked loose and it’s moving, switch from the stubby starter to a regular roll pin punch to push the pin all the way out the other side.

Starting with a Brownells Premium 1-Inch Delrin Tipped 8-ounce Brass Hammer will keep you from bending punches and marring finishes. At some point, you’re going to want a bit more smack and something like a Williams 20543 12-ounce Ball Pein Hammer will let you apply more force exactly where you need it.

There aren’t many screws on a stock AR-15; you might find one holding the grip on the lower receiver. But, updated guns, and updating guns, will call for a driver to install and work on many aftermarket handguards. A ¼-inch bit holder with a spread of quality bits will offer a lot of versatility without taking up a lot of room in your toolbox. The shorter the bitholder handle, the easier it is to control. We have a Brownells Magna-Tip Standard Set No. 1 with LE Handle. The LE handle is longer than a stubby, but shorter than a regular length handle. Some bit holders retain bits in the head with a magnet, some use a mechanical clip. Preference is up to the user; magnetic bits are fast to swap, but they tend to stick in the bolt heads. Clip holders retain the bit using a thin wire that catches a detent on the side of the bit. We find this system a little more secure, but the holding wire will eventually wear out. You’ll want an array of ¼-inch shank Torx, Phillips head, slotted head, and hex head bits to cover all your bases. While a bit holder will offer the most versatility, hex keys are fast and the short end of these tools are great for breaking loose, stuck bolts. Just be careful; poor-fitting driver heads made from cheap metal will strip out, or worse, strip out a screw before you realize how screwed you are. If you’re working on a gun with lots of bolts, or you just like nice things, have a look at a Wera 816 RA ratcheting bit driver. It’s a European company known for technician’s tools of exceptional quality. Think of the kinds of tools Formula 1 and MotoGP technicians use and you’re there. The smooth action, short handle, and autolocking collar combine to make a lustworthy tool that’ll find you looking for things to fix just so you can use it.

ar-armored-tools-the-basics

1 Brownells Roll Pin Punch Set
MSRP: $20
URL: www.brownells.com

2 Brownells Premium Roll Pin Holder Set
MSRP: $32
URL: www.brownells.com

3 Brownells Roll Pin Starter Kit
MSRP: $35
URL: www.brownells.com

4 Brownells Premium 1-inch Delrin Tipped Brass Hammer 8 oz
MSRP: $22
URL: www.brownells.com

5 Williams 20543 12 oz Ball Pein Hammer
MSRP: $20
URL: www.snaponindustrialbrands.com

6 Brownells Magna-Tip Standard Set No. 1 w/ Clip Tip LE Handle
MSRP: $50
URL: www.brownells.com

7 Wera 816 RA Ratchet Screwdriver
MSRP: $40
URL: www-us.wera.de

Holding it Down

The backbone of an armorer’s den is the bench and vise. A workbench of nearly any size will accommodate an AR. Something as small as two 2×3-foot sheets of ¾-inch plywood glued together and mounted to sawhorse legs will work, so long as it’s stable enough to hold a vise. The vise is your brawny, third hand and its value is in its ability to hold resolutely, move smoothly, and last forever. The vise you’ll want will have at least 4-inch jaws. Six inches will give you better purchase (more clamping area), but we’ve found 4-inch jaws work well enough holding common AR fixtures that it’s hard to justify the added size, weight, and expense of a much larger vise.

You’ve got three routes to a vise. You can get a decent quality bench vise from Harbor Freight or any big-box hardware store. You’re likely looking at a cheap cast-steel body that’ll hold up for a while before something chips or bends. Another option is to pay beaucoup dollars for a brand-new, heirloom quality Wilton machinist vise. A thousand bucks will get you a great ductile iron vise with a shrouded main screw that will outlive your grandkids’ grandkids. But, the best option is to hit Craigslist and find an older, high-quality bench vise that’s of no more use to its liver-spotted owner. Look for older Wilton, Columbian, Ridgid, Record, Reed, and Yost vises. Don’t worry about surface rust; pay attention to the jaws and the action. Look for jaws that are square to one another and don’t wiggle. Movement of the main screw should be smooth, and jaw pads should be without deep scratches or burrs. Just be aware there are vise geeks out there collecting the good ones to refurbish and resell. When you bring your vise home, clean it up, lube the main screw with plenty of grease, and mount it with a few 3⁄8-inch bolts.

Fix and Finish

A vise alone is great for holding anything solid with a two parallel faces, of which there are zero on an AR. Rather than crush aluminum receivers in vise jaws or curse the odd, unhandlable shapes of gun parts, we look to fixtures as the savior of our sanity. The first fixture you’ll likely encounter in the AR world is the simple lower receiver vise block. Slip one half of the block into the magwell of an AR lower and tighten a vise on the other, exposed portion, and the receiver is going nowhere while you install the receiver extension and most of the lower parts kit. The basic Brownells version has been around forever, but take a look at the Magpul BEV Block. It’s a couple of fixtures in one. Not only is it a great lower receiver vise block, its primary duty is holding an upper receiver while preventing the barrel extension from turning when installing a new barrel, muzzle device, or handguard. It does this by engaging the chamber lugs on one end, and snapping the bolt carrier into the other for a wobble-free mount. While the BEV is versatile, the Geissele Reaction Rod is the most elegant and bombproof way to work on an upper receiver yet invented. Set the flats of the rod in a vise and slip the upper on it like a mandrel. The splines on the fixture engage the barrel extension and hold it immobile while installing a barrel, gas block, handguard, or muzzle device. The best feature is its speed. There’s nothing to lock, snap, or twist to lock the barreled upper receiver. Want to rotate the upper for a better angle? Slip it out an inch, rotate, and slide it back on so the splines reengage the barrel extension. The Wheeler Engineering Delta Series AR Upper/Pic Rail Vise Block, comes in handy when lining up the top rail of a handguard with the upper receiver rail. It’s a great value since it also does the job of an upper receiver block on both AR-15 and AR-10 platforms. The Geissele Reaction Block is an alternative to the standard lower receiver vise block. It captures the receiver extension in one of four positions, allowing you to work with the sides of the lower facing up in addition to the straight up and down orientation you get with a regular vise block. It also takes the stress off the receiver when tightening the receiver extension nut; handy for polymer receivers, but overkill for aluminum. The Wheeler Engineering AR Armorer’s Bench Block is a multi-use fixture that holds receivers, charging handle, and front sight post steady while driving pins. It’s a great way to save some frustration while working on a standard receiver set; just be aware that it’s not going to work with thick polymer receivers.

ar-armored-tools-fix-and-finish

1 Magpul Bev Block
MSRP: $50
URL: www.magpul.com

2 Geissele AR15/M4 Reaction Rod
MSRP: $99
URL: www.geissele.com

3 Wheeler Engineering Delta Series AR Upper / Pic Rail Vise Block
MSRP: $54
URL: www.btibrands.com

4 Geissele Reaction Block
MSRP: $99
URL: www.geissele.com

5 Wheeler Engineering AR Armorer’s Bench Block
MSRP: $60
URL: www.btibrands.com

Gas and Lube

Adding a free-float handguard is probably the most common job performed on the AR platform. In nearly all cases, this means taking the front sight base/gas block off the gun and replacing it with a low-profile block that fits under the new handguard. It’s a frightening job that seems like a heart transplant. But, with the proper tools, it’s about as stressful as performing an oil change. Getting a well-seated taper pin moving can bend a standard punch. For this, use a Starrett Taper Pin Starter and finish with a regular punch. Once the FSB is off the barrel, use the Geissele Gas Block Pin Punch Set to get the tiny, 0.078-inch gas tube roll pin out. To get it back in, use the Precision Reflex, Inc Gas Block Assembly Fixture. It comes with a roll pin holder sized for the gas tube roll pin. Lay your low-profile gas block in the fixture and tap away. Without a fixture like this, the gas block sits at an odd angle, and it’s very easy for punches to slide off as you try to tap the gas tube roll pin in. Occasionally, you may run into a taper pin that doesn’t respond to your gentle taps while trying to drive it home. You might use a Drillco 4550E Series 2/0 HS Steel Taper Pin Reamer to clean up tapered gas block and barrel holes before resorting to the Big Hammer. More than likely, though, you’re replacing a FSB with a low-profile gas block that uses set screws to hold it in place. The easiest way to install a set screw gas block is using a fixture like the BRD Gas Block Dimple Jig. Slide the jig on your barrel, use the locator pin up top to find the gas port, then use the two guides on the bottom to drill dimples in the barrel. Replace the jig with a gas block and tighten the screws. With the gas block screws in the dimples, the gas block isn’t moving. HB Industries Gas Block Alignment Pins are a handy way for the anal-retentive to make sure the gas block hole is lined up with the gas port. With the gas block off the gun, drop one of the pins into the port, slide the gas block on and turn the upper assembly upside down and wiggle the gas block ’til the pin drops and you’re aligned. Tighten the gas block retaining screws, use a cleaning rod to snap the plastic pin, and drive out both halves.

Turning to friction, and the chemical control of said phenomenon, let’s talk installation lube and threadlock. While there are many opinions on what lubricant to use when installing a barrel nut, everybody agrees the barrel nut should have some lube to help it achieve the proper torque and protect the threads of the dissimilar metals from galling. The longtime standby is AeroShell Grease 33MS because it meets the Mil-spec standard the DoD applies to barrel nut lubricants. Buying it in a commercial tube will give you enough grease to last five lifetimes, so look for resellers that repackage the stuff and sell a few ounces for a few bucks. It won’t hurt to dab a thin layer on the barrel extension before sliding it into the upper. If you ever have to take that barrel out, you’ll thank us for reminding you. An alternative to AeroShell recommended by Robb Jensen is Weapon Shield Grease. The lithium-based grease won’t hold up to the high temps of the AR chamber as well as the Moly-based Aeroshell, but it’ll get you torqued and set just as well. You just might not have it as easy pulling the barrel apart a few years down the road than if you used the Aeroshell.

On the other end of the spectrum, some AR jobs call for thread-lock to keep screws and bolts from backing out. It’s mostly used to keep the screws in aftermarket free-float handguards from falling out. If you’re still using the squeeze bottle, drop applicator, you’re in for a treat. Check out the new Permatex 27010 High Strength Threadlocker Red and 24010 Medium Strength Threadlocker Blue Gel. These gel formula thread-lockers make application so much easier and cleaner, you’ll feel like a caveman going back to the liquid Loctite in the drip bottle.

ar-armored-tools-gas-and-lube

1 Starrett Taper Pin Starter
MSRP: $13
URL: www.brownells.com

2 Geissele Gas Block Pin Punch Set
MSRP: $25
URL: www.geissele.com

3 Precision Reflex, Inc Gas Block Assembly Fixture
MSRP: $30
URL: www.precisionreflex.com

4 Drillco 4550E Series HS Steel Taper Pin Reamer 2/0 size
MSRP: $20
URL: www.drillco-inc.com

5 BRD Gas Block Dimple Jig
MSRP: $65
URL: www.brdengineering.com

6 HB Industries Gas Block Alignment Pins
MSRP: $9
URL: www.brownells.com

7 Aeroshell AeroShell Grease 33MS 5% Molybdenum Disulphide Grease
MSRP: $3
URL: www.shell.com

8 Weapon Shield Grease Lithium Grease
MSRP: $9
URL: www.weaponshield.com

9 Permatex 24010 Medium Strength Threadlocker Blue Gel
MSRP: $12
URL: www.permatex.com

10 Permatex 27010 High Strength Threadlocker Red Gel
MSRP: $12
URL: www.permatex.com

Lowdown and a Little Dirty

Attacking the lower AR receiver is pretty painless once you have a few tricks under your belt. Every armorer has their most hated point in the lower build. Some fear crushing the trigger guard ears with a hammer and punch and instead use a press such as the Little Crow Gunworks Roll Pin Pusher. This little guy slowly pushes the trigger guard roll pin in and out, making alignment and insertion a breeze. Other guys have launched so many forward takedown springs and detents from their benches that they won’t build a lower without a Brownells Forward Takedown Pin Insertion Tool on hand. Though this tool is longer and easier to use, an alternative is a ¼-inch x 2-inch Clevis Pin from any hardware store. Both let you press the spring and detent into the recess using something like a heavy-gauge paper clip (shown), hold it there as you press the takedown pin against the face of the tool and push it back through so the detent takes hold of the takedown pin as it passes over. Another, why-oh-why operation is driving the bolt catch pin in place. It’s common to see lowers that bear the scars of a newb armorer’s hammer or punch that’s skipped off and gouged the lower’s virgin skin. Applying some masking tape will help, but getting some space to work the hammer is the best play. Little Crow Gunworks’ Bolt Catch Tool does just that. It’s a custom, extended punch set that lets you tap the punch behind the lower without fear of skipping off and causing damage. Tapping trigger and hammer pins in and out of the lower is another easy way to mar metal. Instead of tapping, try the Geissele Trigger Fitting Pin. Cupping the ball end of the pin in your palm lets you apply a lot of force slowly and evenly, taking some of the stress out of the three handed trigger installation job. Lastly for the lower, staking the castle nut couldn’t be faster and easier when using a spring-loaded center punch. A few dozen clicks with the General Tools 89- Stainless Steel Automatic Center Punch will stake a castle nut in a minute or two.

ar-armored-tools-pin-tools

1 Little Crow Gunworks Roll Pin Pusher for AR-15
MSRP: $40
URL: www.littlecrowgunworks.com

2 Brownells Forward Takedown Pin Insertion Tool
MSRP: $16
URL: www.brownells.com

3 Home Depot Clevis Pin
MSRP: $1.57
URL: www.homedepot.com

4 Little Crow Gunworks Bolt Catch Tool
MSRP: $18
URL: www.littlecrowgunworks.com

5 Geissele Trigger Fitting Pin
MSRP: $15
URL: www.geissele.com

6 General Tools 89-Stainless Steel Automatic Center Punch
MSRP: $16
URL: www.generaltools.com

Which Wrench

The spaces beneath armorer’s benches are littered with the carcasses of once favorite armorer’s wrenches. Some break, some rust, some slowly wear out. Once, when the AR was young, there was only the basic G.I. barrel nut — Eugene Stoner’s perfect solution. Its toothed outer ring is both a bearing surface for a wrench and a way to lock the nut using the gas tube. Despite the explosion of free-floating handguards and their necessarily customized barrel nuts, the G.I. barrel nut is still very prevalent. There are a host of other common nuts on the AR, and there’s no end to the amount of armorer’s wrenches that hope to turn them all and claim the title of “last wrench you’ll ever need.” These three might not be the last you’ll ever need, but they will last a long time and have a few unique features that are worth a look.

The Tapco’s Armorer’s Wrench is a worthy wrench that covers all the bases without breaking the bank. The coated surface helps maintain your grip during use and prevents oxidation in storage. While it isn’t the master of any AR bolt, it does seem to have that combination of wrench heads that makes it one of the most versatile tools in its price range. The Magpul Armorer’s wrench is kind of a beast compared to other armorer’s wrenches. It’s the wrench that will beat all other wrenches unconscious and engrave “unfair advantage” on them before curbstomping the pins from their working end. It’s big and fairly thick, giving great leverage without biting your hands. The surface is purposely left a little rough feeling due to the phosphate finish, enhancing durability and grip. The barrel end works on both pin and G.I. nuts, and the other end slips over a barrel extension to give three points of contact on a castle nut. The enclosed end means it’s a tiny bit slower than an open-ended buttstock wrench, but the quality of engagement seems worth the reduced productivity. The wrench isn’t meant to be a 500-in-1 tool, but a super durable wrench that addresses the most common AR needs without much compromise. The Brownells CAR-15/M4 Buttstock Wrench pulls no punches. This wrench isn’t the One Ring at all, it’s an elegant approach to one of the most shortchanged tools on the AR armorers bench. With four engagement points on the castle nut, this is one wrench that won’t slip off and damage the finish of a gun. It’s a stout, thick little wrench that takes care of the back half of an AR like no other wrench we’ve handled. Sure, you could use those $5 stamped metal jobs, but we don’t think you’ve read this far into the article if you’re not a buy-once, cry-once kinda tool shopper.

ar-armored-tools-wrenches

1 Tapco Armorer’s Wrench
MSRP: $45
URL: www.tapco.com

2 Magpul Armorer’s Wrench
MSRP: $80
URL: www.magpul.com

3 Brownells CAR-15/M4 Buttstock Wrench
MSRP: $80
URL: www.brownells.com

Special Needs

Here’s a set of tools that the garage armorer can live without, but having them around will take the uncertainty out of some jobs and allow you to do a few things that can’t be done with a basic set of tools.

Spline rods are hard on barrel pins. If you have a really stubborn barrel nut and are using a splined rod fixture, there’s a chance you could apply enough torque to bend a barrel pin or deform an upper receiver. The Geissele Super Reaction Rod uses the same splined chamber lug interface as the original Reaction Rod, but adds a removable boss that spreads the torque of a PIA barrel nut removal through the upper receiver in a way that minimizes the chance of damaging the gun.

We won’t lie, every armorer we spoke with said it’s a rare day when they reach for an ejector removal tool. It’s pretty unlikely that you’ll see an ejector related problem on an AR. But, that means when someone needs ejector help, they’ll be desperate. You could be a hero if you have a Brownells Ejector Removal Tool on your workbench. While it’s on the pricey side, this tool works on a few different guns including AR-15, AR-10, Remington 700, Winchester 70, Savage, and Sako platforms.

Judging torque isn’t hard, but it takes practice and experience — things that a garage armorer might not develop. A shortcut is having a set torque wrench on hand to make sure you’re not under or overdoing it with the twist. For barrel and receiver extensions, something like the Matco Tools TRB75F 3⁄8-Inch Drive Flex Head Torque Wrench and a ½-inch socket adapter would work as well as a less expensive beam style torque wrench from a hardware store. The advantage of a pro grade torque wrench lies in the fact that you set the torque and the wrench clicks when you hit it. No guessing. The reason for a 3⁄8-inch drive as opposed to a ½-inch is versatility. The 3⁄8-inch works with a common automotive socket set so it can be used for jobs other than working on guns. A torque driver such as the Brownells Magna-Tip Adjustable Torque Handle comes in handy for the same reasons when working on handguards and optic mounts.

Most AR uppers are perfect out of the box, but some aren’t. With the AR market crash of 2014 came a dearth of cheap receiver sets. So, it’s not hard to find a bargain bin upper that has a little bit of run-out on the barrel interface. The Wheeler Engineering AR 15 Receiver Lapping Tool is a simple way to true up the face of an upper receiver. Just apply some lapping compound, slide the mandrel into the upper, attach a drill, and slowly lap the opening into a flat and true face that will fix any barrel seating woes. This has become such a common issue that some professional armorers we’ve spoken with lap all their barreling jobs preemptively.

1 Geissele Super Reaction Rod
MSRP: $175
URL: www.geissele.com

2 Brownells Ejector Removal Tool
MSRP: $64
URL: www.brownells.com

3 Matco Tools TRB75F 3⁄8-inch Drive Flex Head Torque Wrench
MSRP: $333
URL: www.matcotools.com

4 Brownells Magna-Tip Adjustable Torque Handle
MSRP: $150
URL: www.brownells.com

5 Wheeler Engineering AR 15 Receiver Lapping Tool
MSRP: $36
URL: www.btibrands.com

Subscribe to the Free
Newsletter