Building a Tactical AR
September 23, 2010
How the author rebuilt a trusted but well-worn AR-15 into a new tactical tackdriver
Trusty II, after the project, with a Holosight on top and a SureFire 900 light below. For close-range shooting, keep both eyes open, and put the Holosight reticle two inches above where you want the shot to go. With a sling, Trusty II will be complete.
"Trusty" was done. I had been practicing on the rifle-plate rack, and I missed. The day had come; the barrel was done. Many of you might think that I'm being arrogant when I say, "I missed, and the rifle is at fault."
You haven't shot Trusty. I picked up this rifle for a song back in the very early 1990s. Trusty was assembled on an Essential Arms lower. I say "assembled" because Essential never made rifles; the company only made lowers. And then it went out of business. I picked it up for a song because it was "defective." The previous owner had tried to assemble it himself, didn't know what was wrong when it wouldn't work and figured he'd fix it by drilling the gas port larger. Since there is almost no problem that an AR can be heir to that is fixed by drilling the gas port,
I replaced the trashed barrel with a cheap used one. What I picked up was a skinny, 20-inch 1:12 twist off an M-16. It fit the look of the A1 upper and the triangular handguards. What I didn't know was that I had picked up the most accurate barrel Colt ever made.
That skinny barrel was a tackdriver. And miraculously, it shot Winchester 63-grain softpoints like an NRA High Power Match rifle--well, at least to 100 yards, which is all our gun club has. It would plunk five of them into a group you could cover with a single paster. It shot any load with 55-grain FMJs into less than an inch. It was so accurate it wasn't really useful as a test-bed for reloading as it would accurately shoot ammo that wouldn't group in other rifles. I have no explanation for this; I am only reporting what I observed.
I used Trusty and didn't think twice about it. I used it for practice in IPSC 3-Gun and on bowling pins. I set the iron-sight record on our club's rifle-plate/pin rack, five pins off-hand, iron sights at 90 yards, in 4.11 seconds. Later I used it as a loaner when I taught rifle classes. If someone had a rifle that broke, they'd get mine while I fixed theirs. Usually, I had to hunt down the officer involved and force him to take his departmental rifle back because his scores were invariably better with Trusty than with his issued rifle.
On the fateful day when Trusty failed, the sights were centered on the pin, and the trigger broke cleanly. The pin should have fallen, but it didn't. So I promptly set up the shooting bags and shot a group off the bench--a disappointing three inches at 100 yards. Perhaps the bore was just copper-fouled; I cleaned and retested. No change. Time for a new barrel.
While I was at it, why not make a few other changes, too? Why not build a new tactical AR on the base of my old A1 rifle? The first task was to decide what to change.
When you slide the stock off, be sure you don't lose the rear takedown retainer-pin spring and plunger.
The barrel had to be a faster twist to allow the use of heavier bullets. As I already have plenty of full-size rifles, I went with a 16-inch barrel. Brownells carries many, and I'd always heard good things about DPMS, so I had the folks at Brownells ship me an M-4-looking shortie barrel. (I actually ended up with two, a subject for a later article.)
Now, should I simply use the existing upper or change that, too? Essential Arms receivers were cast, and they looked it. The upper was serviceable, but the carrying handle was clumsy when it came to mounting optics, lights or anything else. EGW provided a flattop upper with integral Picatinny rail.
Earlier, at the SHOT Show, Brant Sabau, national sales manager of GG&G, had tempted me with the company's new free-float tactical handguards. "Sure, we can send you a set." Great, the upper was all set.
Or was it?
To access the batteries on the Vltor stock, you turn the latch and pull it forward until it comes free.
Wait a minute: A flattop upper lacks sights. I placed a quick e-mail to Brant and soon had a folding rear sight in the mail. The new GG&G folder has a built-in lock, so once you stand up the sight, it won't get knocked down.
Since EOTech is a neighbor, it was an easy choice to clamp on its Holosight as the optical sighting system. For most work I'd use the Holosight, but in the case of battery or catastrophic electronic failure, I can pop the irons and keep going.
With the choice of upper settled, there was the matter of the legal status of the lower. As the Essential Arms Company went out of business years before the Assault Weapons Ban was passed, and I had this rifle in my possession before the ban was signed, there is no question that it is a pre-ban gun. As a result I could not only have the DPMS barrel shipped with muzzle threads, I could swap the fixed stock for a tele (remember, even if the ban has sunset when you read this, I'm building it before the sunset date).
But which telescoping stock?
There are many, and one thing you should know is that there are mil-spec (or Colt) tele stocks, and then there are all the others. If you have a Colt or mil-spec buffer tube, you can swap Colt or mil-spec tele stocks on it. If you have a "non" (non-Colt or non-mil-spec), you can't.
Another tempting product I discovered was the Vltor tele stock. Its mil-spec-compatible stocks recognize tactical realities and have integral battery storage.
Shortie stocks get the short buffer and spring, above. Standard ones use the longer buffer and spring.
n to building the new Tactical AR. The first thing to do is check headspace of the new barrel. I stripped the bolt, removing the extractor and ejector from the bolt head, and with Dave Manson headspace gauges, I found the chamber to be too short. Perfect. I then reamed the chamber and checked the headspace until the chamber would just accept a "GO" gauge but not a "NO-GO" gauge. If in testing I find the chamber is still a bit too short for reliable function, I can always ream a little bit more.
Next we installed the barrel into the upper. Unlike many other rifles where the barrel screws into the receiver, the AR barrel is clamped into the receiver via a barrel nut. Trusty is getting a free-float handguard, so the delta ring, spring and C clip that would retain the regular handguards aren't needed. As the EGW is a flattop upper, I couldn't clamp it in my standard AR upper blocks and had to use barrel blocks.
The Vltor stock, with its battery-storage compartments, provides a wider and more comfortable cheekrest.
No problem. I clamped the barrel, slid the receiver onto the barrel extension and spun the nut on. With a barrel-nut wrench (I favor one made by American Spirit Arms--it is tough and has a long handle for lots of leverage), I tightened the nut; loosened, tightened and loosened. The idea is to burnish the mating surfaces together before the final tightening. Barrel nuts, according to military specs, are tightened to 35 ft-lbs or until a notch in the barrel nut lines up with the gas-tube clearance hole.
In my experience, the accent is on the "until" part. I've run into factory ARs where the barrel-nut torque was more than 75 ft-lbs, and I've even seen a few that I had to cut off. Tighten as much as you can, until a notch lines up. If no amount of force will tighten the nut enough, you'll need to find a gunsmith who can dress the front face of the receiver back and allow nut movement.
Trusty's tightened right to the perfect 12 o'clock position at just under 50 ft-lbs. That done, I slid the gas tube through the nut and receiver and then fished the other end into the front-sight post. Once it lined up, I tapped in the gas-tube pin, locking the gas tube in place. The GG&G free-float handguard then clamps over the barrel nut with six Torx screws. As final assembly of the upper, I put an A2 flash hider on the muzzle and a regular front-sight post--four position--into the front-sight housing.
While AR cognoscenti look down on lowers built by Essential, I have found this one to be dimensionally correct. The first thing I did when I received the upper was to check and make sure it fit. Uppers and lowers are supposed to be interchangeable, but with so many makers of both, you can easily find sets that don't mix and match. The EGW was a snug fit onto the Essential lower. That settled, I unscrewed the top bolt in the buttplate and pulled off the stock. With the buffer tube uncovered, I could see the rear takedown-pin detent spring sticking out of the lower. I pulled out the spring and detent plunger and set them aside. They are easy to lose in this step, and if you aren't careful you can be waiting for the next box from Brownells to finish your work.
I clamped the lower in a padded vise and grasped the buffer tube with both hands. Standard buffer tubes should not be wrung on with a wrench and absolutely should never be secured with a thread-locking compound. The tube proved resistant, so I carefully used a wrench to break it loose, then finished turning it by hand. Again, be careful with the buffer retainer and spring.
To attach the new buffer tube, install the retaining plate and nut, with the plate and its convex lump toward the tube opening and the nut behind it (closer to the buttplate) with its larger open ends toward the buttplate. Turn the buffer tube by hand until it almost covers the buffer retainer spring and plunger. Then press down the retainer, and give the tube another turn or two. You want the tube to keep the retainer in but without locking it down.
The GG&G fold-down rear sight, shown in both positions. When upright, it locks into place so it won't inadvertently be lowered.
Next, install the rear takedown plunger and spring, and slide the retaining plate down to compress the spring. Turn down the locking nut until it secures the retaining plate. Make sure everything is lined up before you tighten the locking nut. Some like to use an application of a threadlocking compound to keep the nut secure. I prefer to stake the nut.
Now slide the stock onto the tube. When the locking lever stops against the tube, pull down firmly on the stock lever to clear the back of the tube (not just levering it), and once the bolt clears the rear of the tube, press forward. Once it has started, you can let go of the lever, and the locking lever will snap into the first stop hole it encounters.
With the rails contiguous, you can mount the Holosight anywhere along the rail (left). If you don't like the light handle this close, switch the bottom rails on the handguard, and mount the light farther out (right).
The Vltor stock then simply requires you to select which combination of stock plates or battery compartments you want installed, and snap them in place. With either the storage tubes or the plain cheekpiece (or a combination) on the buttstock, tighten the clamping bolt through the bottom flange. To seal the storage compartments, you need to press firmly on the seal caps, then turn them to the inside. They won't go easily, but if you want a watertight seal, you have to work for it.
The only choice left is to use the top sling loop or an Uncle Mike's quick-detachable loop. I installed the Uncle Mike's, then found myself in a pickle. I hadn't planned on where to install the front loop. What to do without spending a lot of time hunting down sling-swivel mounts to go on the handguard? I dug in the parts drawer again and came out with the GG&G Sling 'n Light Combo. The SliC clamps in the front-sight tower and provides a sling location and a rail to mount a light should I need another rail.
All that was left in the lower was to install the new buffer and spring. As the tele stock buffer is shorter, I couldn't use the regular buffer and spring, so I pulled a shortie buffer and spring out of the parts drawer. With a little lube and a quick install, "Trusty II" was ready to go.
The only things left were to zero and test
before using it in matches, classes or to keep handy in emergencies.
Trusty II, all set for final testing and then for the ready rack.
Zeroing the AR
The standard military zero for the M-16 and M4 is to have the point of aim and point of impact at 41 meters, which delivers the downrange point of aim/point of impact again at 250 meters. The problem is, most encounters are inside 100 meters, especially in law enforcement and defensive use. With the military zero, your point of impact is under your point of aim inside 40 meters and above past that. I prefer the "competition zero," or as my friend Jeff Chudwin calls it, the "law enforcement zero." The point-of-aim/point-of-impact initial zero is pushed back to 100 yards. With that zero, every shot inside of 100 yards has the point of impact below the point of aim--but not much, as the bore is 21⁄2 inches below the sights.
Across a room, you'll have to remember that your hits will be low, but you'll have to do that with the military zero, too. With this zero, your hits will be 2.23 inches low at 200 yards and 14 inches low at 300. Most encounters will be well inside 200 meters, and across that distance your point of impact will never be farther than 21⁄2 inches from your line of sight; the greater drop past 200 is something I can live with.
For basic zero you'll find that the bullets will impact the target an inch and a half low at 25 yards. To account for that, we've designed a target with an obvious aiming point but with an indicator circle to show correct impact. Another of my Chicago friends, Loren Helwink, then redesigned the target with the sight adjustments printed right on it. The Chudwin/Helwink target is the fastest and easiest target I've ever used to get a rifle zeroed. And the Tactical Essential was no different.
I needed three groups: a three-shot for vertical adjustment, a three-shot for horizontal and a five-shot to make sure. With 11 rounds, I had the iron sights zeroed. I then turned on the Holosight and adjusted it until the dot was perched on the front-sight post. As I was all set to do the 100-yard check, I swabbed the bore with Shooters Choice Copper remover before walking to the 100-yard line to post a target. Once back, I dried the bore with patches and shot a five-shot group. Looking through the binoculars, I needed one click left and one click down to be spot-on. I then folded down the GG&G rear sight, turned the Holosight back on and fired another group. It, too, needed a grand total of three clicks to be finished.
Trusty II with the zero target. To account for the fact that the bullets will impact about 1.5 inches low at 25 yards, the author came up with this special target.
With Trusty II zeroed, I now needed to make sure it was reliable. I spent an afternoon working over the falling plates, putting 200 rounds downrange. With both the Holosight and the iron sights, I was able to easily drop the plates (90 yards downrange, roughly bowling-pin size and shape), but the Holosight was faster. The empties ejected slightly forward and seven to eight feet to the right.
For the final test before depending on Trusty II in a match, I put it away without cleaning it (yes, Sweeney the Heretic strikes again). I left it uncleaned until the next range session, so the powder residue in the chamber could harden into a tough scale. On the next session, a week later, I brought some of my old pin-shooting ammo, which uses a Winchester 63-grain softpoint over enough BL-C2 to get just more than 2,200 fps in a 16-inch barrel and almost 2,300 in a 20. The load is soft in recoil, plenty accurate (under one inch in Trusty), took the pins over with power to spare and would choke any AR that was the least bit inclined to malfunction. All my rifles shoot it reliably, and now Trusty II joins that group. Even with lightly loaded ammo it worked reliably right from the start.
I find that the Vltor stock with the battery-storage compartments installed is a very comfortable stock. One problem with the AR design, and the tele stock in particular, is cheekweld. It's a skinny place to put your face. The Vltor has enough bulk, and it uses a comfortable plastic composition that makes it a lot more comfortable than regular stocks. With the Holosight on top, I know I have spare batteries for it. On the other side of the stock I can keep spare batteries for whatever light I might be using.
The only thing left was to start using Trusty II in the club three-gun matches and haul him along to the classes for future students to use.
It's all in the wrist. The 2 o'clock postion of the one-piece JP auxiliary iron sight also allows for super-fast engagment of close targets.
When the word "tactical" gets added to the conversation, the mind immediately springs to images of black or camo guns loaded with rails, lights, sights and sometimes even a night-vision optic or laser-targeting designator. And often the image includes lots of dust, mud and finishes worn through to bright metal. John Paul doesn't hold with that, and his rifles look like they might be right off of Darth Vader's weapons rack.
He sent me a CTR-02 with all the bells and whistles for competition, but it is also useful in many tactical contexts, too. John makes his rifles by milling the uppers and lowers from billets of 7075 aluminum. They are precisely fitted, and then the receivers and the handguard tubes are hard-coat anodized.
Besides the shape of the receivers, what also distinguishes a JP Enterprises rifle from others are the colors. While this one came in basic Darth Vader black, you can have yours in a variety of eye-searing colors. On top was a Trijicon TA01 Acog with a reticle trajectory-matched to .223 match ammo using 69-grain Sierra match bullets. The reticle is illuminated via a tritium insert, so as you lose the light, your reticle appears to begin glowing red (it's always been there, just too faint to see). So in low light you won't lose your reticle to the darkness. Curiously, John said he zeroed it for 200 yards, but when I tried it, the five shots at 100 yards clustered on and around the paster I was using as my aiming point. The 20-inch barrel made of 416 stainless is a special JP barrel cryogenically frozen to reduce stress and enhance accuracy, with a 1:8-inch twist.
Fresh off Darth Vader's weapons rack: JP's Competition Tactical Rifle has what it takes to compete or survive close encounters of the ballistic kind.
The barrel has an integral muzzlebrake, and, as with all muzzlebrakes, it makes shooting easier but makes spotting for the shooter, well, interesting. As long as you don't stand, sit or lie down in the backblast you'll be fine. If you are in the blast path you'll know it immediately. The brake works so well you can easily spot your own hits on steel plates from watching the puff of paint and lead created by the hit.
The gas block is a JP block with a gas-system adjustment nut. You can open or close the gas system to tune it with the ammo you've found to be most accurate and to help dampen recoil a bit. I found it accurate with a wide variety of ammo. The handguard has the JP short-range sight mounted forward and at about 2 o'clock relative to the line of sight. Rather than try to use the Acog on very close targets, just rotate the rifle slightly on your shoulder to bring the short-range irons in line, and you've got a super-fast sight to nail close targets. The handguard also has sling-swivel hardware that can be loosened and slid along the cooling slots to locate your sling (or other gear) wherever you want.
If you don't want to shoot with optics, the upper receiver and adjustable gas block have rails, and you can attach regular or folding sights. Those who shoot in USPSA Limited Division in three-gun matches, or enter tactical matches that require iron sights, can easily bolt on sights.
The upper has no dustcover in the ejection port, nor a forward assist. Keep it relatively clean, and it won't fail you. Neglect it, and it probably will.
The stock has yet another trick custom feature: a magazine holder. The holder clamps on the ribs of the magazine to hold it in place. I couldn't get the magazine to jar loose with any kind of running, jumping or inadvertent barricade bashing. It will stay put in a match. I'm not so sure it would survive a parachute drop, but since I don't do that, and this rifle is meant for matches and perhaps automobiles, I see the magazine staying securely attached. To reload, just get your fingers on the end of the magazine, tip the mag and holder out of the stock a bit (the whole rod the rail is attached to pivots), and then yank it free. The buttplate is adjustable for drop and cant. If you find that you can't get a standard buttstock comfortably on your shoulder, the JP unit can be adjusted to fit you. On the exposed buffer tube is a foam-rubber sleeve that works brilliantly as a cheekpiece.
The trigger John sent me in this rifle is a prototype of his new drop-in unit. On all other ARs you have to tune and adjust the trigger by making adjustments, assembling, checking, disassembling and making yet more adjustments. There are some triggers where you can make basic adjustments with the trigger assembled.
In the new JP unit, you can do all your adjustments with the entire fire-control unit out of the rifle yet still assembled. Once it is to your liking, press the assembled block down into the lower, push the cross pins through, and stick on their C-clips to prevent walking. If you want to take it out for cleaning, you take off the C-clips, press the pins out and remove the whole assembly. You can soak it to clean it and rest secure in the knowledge that you haven't made any changes to your settings. As the one John sent broke at a nice, crisp three pounds, I didn't have any desire to go fiddling with it just to see how the adjustments worked.
But enough of the drooling over looks; how does it shoot? To coin a phrase: like a house afire. I took it along on a class to see how it handled, and once I'd verified the zero, I shot it through a few drills. As you can imagine, using a rifle this sophisticated on a state qualification course is like slinging a Lamborghini through a patrol-car road course. It was almost like cheating; the rifle almost won't let you miss, and I shot a passing score.
To give the JP a better workout, I then took it to the next range and shot the National Guard 300-meter popup course. There, you get hit-sensitive plastic targets that a computer stands up each in turn, from 50 to 300 meters. If you hit it, the computer hauls down the target and gives you credit. If you miss, it leaves each up until time expires, then hauls it down and gives you a zero on that target. From the concrete foxhole, I got 20 hits on 20 targets--too easy. So I switched to the left shoulder and shot the whole course again from the weak side--again, too easy as I went 20 for 20.
OK, let's see if I can show off. I shot the course standing and once again posted a 20-20. I figured 60 straight hits was enough, and I quit. A few others in the class also had a go with it and commented favorably on the looks, trigger, optics and performance.
Back at my home range, close drills showed the superiority of the iron sights on the handguard to the optics. With the 20-inch barrel, it is a bit long to fit some rifle racks, but JP will gladly make you one with a 16-inch barrel if that's what you need. For street or range, the JP delivers.