by Dennis Santiago
Tricked-out match guns are fun but, if you want to prove that you’ve got an eagle eye and steady hands, a true test of skill is the Civilian Marksmanship Program’s As-Issued Four Gun Aggregate.
The Four Gun Aggregate encompasses a series of CMP John C. Garand 30-shot matches (200-yard As-Issued Military Rifle Match Course A) on NRA SR targets at one of the CMP Regional Games or the Nationals officiated by the CMP. These are the only places you can earn the coveted neck-ribbon CMP achievement medals.
You will need four as-issued rifles. The first is the M-1 Garand. (The course of fire is named after this rifle’s inventor.) This remarkable battle rifle will test your prowess at slow prone, rapid prone, and offhand. The match winner will put almost all bullets into a saucer.
You do get to hear that classic “ping” when the en bloc clip ejects with this gun. It’s a good idea to write your firing point number on your hand for each match because you will move around over the course of the tournament.
Next comes the hyper-accurate 1903 Springfield. You can use either the WW I M1903 or the later WW II M1903A3 model with peep sights. A Springfield will typically shoot groups half the size of a Garand with the same ammunition. Think potential in terms of tea cups instead of saucers.
A lot of claims are made about accuracy for AR-platform rifles, but much of that is just “sales talk”. But if you want a truly accurate black rifle, there are some key upgrades that, collectively, can transform a plain jane AR into a true tack-driver. Here’s an article by a genuine AR expert that will help you identify those components that really make a difference — the parts that can deliver true “match-grade” accuracy. Built right, a modern AR can deliver half-MOA accuracy with handloads. In this article, Robert Whitley explains how that’s done.
In our Shooters’ Forum, one member recently asked: “What makes an AR accurate? What parts on an AR can really affect accuracy — such as free-floating handguards, barrels, bolts, bolt carriers?” Robert Whitley posted a very comprehensive answer to this question, based on his experience building and testing dozens of AR-platform rifles. Robert runs AR-X Enterprises, which produces match-grade uppers for High Power competitors, tactical shooters, and varminters.
Building an Accurate AR — What is Most Important
by Robert Whitley
There are a lot of things that can be done to an AR to enhance consistent accuracy, and I use the words “consistent accuracy” because consistency is a part of it (i.e. plenty of guns will give a couple great 5-shot groups, but won’t do a very good 10- or 20-shot groups, and some guns will shoot great one day and not so good on others).
Here are 14 key things we think are important to accuracy.
1. Great Barrel: You’ll want a premium match-grade barrel, well-machined with a good crown and a match-type chambering, true to the bore and well cut. The extension threads must also be cut true to the bore, with everything true and in proper alignment.
2. Rigid Upper: A rigid, heavy-walled upper receiver aids accuracy. The typical AR upper receiver was made for a lightweight carry rifle and they stripped all the metal they could off it to make it light to carry (which is advantageous for the military). The net result are upper receivers that are so thin you can flex them with your bare hands. These flexible uppers are “strong enough” for general use, but they are not ideal for accuracy. Accuracy improves with a more rigid upper receiver.
3. True Receiver Face: We’ve found that truing the receiver face is valuable. Some may argue this point but it is always best to keep everything related to the barrel and the bore in complete alignment with the bore (i.e. barrel extension, bolt, upper receiver, carrier, etc.).
4. Barrel Extension: You should Loctite or glue the barrel extension into the upper receiver. This holds it in place all the way front to back in the upper receiver. Otherwise if there is any play (and there typically is) it just hangs on the face of the upper receiver completely dependent on the face of the upper receiver as the sole source of support for the barrel as opposed to being made more an integral part of the upper receiver by being glued-in.
5. Gas Block: You want a gas block that does not impose pointed stress on the barrel. Clamp-on types that grab all the way around the barrel are excellent. The blocks that are pinned on with tapered pins that wedge against the barrel or the slip on type of block with set screws that push up from underneath (or directly on the barrel) can deform the bore inside of the barrel and can wreck the accuracy of an otherwise great barrel.
6. Free-Float Handguard: A rigid, free-float handguard (and I emphasize the word rigid) really makes a difference. There are many types of free-float handguards and a free-float handguard is, in and of itself, a huge improvement over a non-free-float set up, but best is a rigid set-up. Some of the ones on the market are small diameter, thin and/or flexible and if you are shooting off any type of rest, bipod, front bag, etc., a rigid fore-end is best since ARs want to jump, bounce and twist when you let a shot go, as the carrier starts to begin its cycle before the bullet exits the bore.
7. Barrel Contour: You want some meat on the barrel. Between the upper receiver and the gas block don’t go real thin with a barrel (we like 1″ diameter if it’s workable weight-wise). When you touch off a round and the bullet passes the gas port, the gas system immediately starts pressuring up with a gas impulse that provides vibrations and stress on the barrel, especially between the gas block back to the receiver. A heavier barrel here dampens that. Staying a little heavier with barrel contour through the gas block area and out to the muzzle is good for the same reasons. ARs have a lot going on when you touch off a round and the gas system pressures up and the carrier starts moving (all before the bullet exits the bore) so the more things are made heavier and rigid to counteract that the better — within reason (I’m not advocating a 12-lb barrel).
8. Gas Tube Routing Clearance: You want a gas tube that runs freely through the barrel nut, through the front of the upper receiver, and through the gas key in the carrier. Ensure the gas tube is not impinged by any of them, so that it does not load the carrier in a stressed orientation. You don’t want the gas tube bound up so that when the gas tube pressures up it immediately wants to transmit more force and impulse to the barrel than would normally occur. We sometimes spend a lot of time moving the gas block with gas tube on and off new build uppers and tweaking gas tubes to get proper clearance and alignment. Most gas tubes do need a little “tweaking” to get them right — factory tubes may work OK but they typically do not function optimally without hand-fitting.
9. Gas Port Tuning: You want to avoid over-porting the gas port. Being over-gassed makes the gas system pressure up earlier and more aggressively. This causes more impulse, and increases forces and vibration affecting the top end and the barrel. Tune the gas port to give the amount of pressure needed to function properly and adequately but no more.
10. Front/Back Bolt Play: If accuracy is the game, don’t leave a lot of front/back bolt play (keep it .003″ but no more than .005″). We’ve seen factory rifles run .012″ to .015″ play, which is OK if you need to leave room for dirt and grime in a military application. However, that amount of play is not ideal for a high-accuracy AR build. A lot of front/back bolt play allows rounds to be hammered into the chamber and actually re-formed in a non-consistent way, as they are loaded into the chamber.
11. Component Quality: Use good parts from a reputable source and be wary of “gun show specials”. All parts are NOT the same. Some are good, some are not so good, and some aftermarket parts are simply bad. Don’t be afraid to use mil-spec-type carriers; by and large they are excellent for an accuracy build. Also, remember that just because a carrier says “National Match” or something else on it does not necessarily mean it’s any better. Be wary of chrome-plated parts as the chrome plating can change the parts dimensionally and can also make it hard to do hand-fitting for fit and function.
12. Upper to Lower Fit: A good upper/lower fit is helpful. For quick and dirty fit enhancement, an Accu-Wedge in the rear helps a lot. The ultimate solution is to bed the upper to a specific lower so that the upper and lower, when together, are more like one integral unit. For the upper receivers we produce, we try to get the specs as close as we can, but still fit the various lowers in the market place.
13. Muzzle Attachments: Don’t screw up the muzzle (literally). Leave as much metal on the barrel at the muzzle as you can. People like to thread the muzzle for a flash hider, suppressor, muzzle brake, or some other attachment, but if you really want accuracy, leave as much metal as you can there. And, if you have something that screws on, set it up so that it can be put on and have it stay there without putting a lot of torque and stress on it right where the bullet exits the bore. If you are going to thread the end of the barrel, make it concentric with the bore and make sure what you screw on there is as well. For all muzzle attachments, also ensure that the holes through which the bullet passes through are dead true to the bore. Many aftermarket screw-on things are not so good that way. Anything that vents gas should vent symmetrically (i.e. if it vents left, it should vent equally right, and likewise, if it vents up, it should vent down equally). Uneven venting of gas can wreck accuracy.
14. Quality Ammunition: Ammo is a whole story by itself, but loads that are too hot typically shoot poorly in an AR-15. If you want accuracy out of an AR-15, avoid overly hot loads. Shown below are test groups shot with four (4) different uppers, all with moderate loads. These four uppers all pretty much had the same features and things done to them as explained in this article, and they all shot great.
NOTE: Despite the “BLK” in the name, this is a NOT a black powder substitute. This is a modern smokeless powder suitable for a wide variety of popular cartridges.
Hodgdon has announced a new “faster” variant of its popular CFE 223 powder. That’s good news for shooters of small varmint cartridges. Hodgdon’s new CFE BLK (named after the .300 AAC Blackout cartridge) has a faster burn rate than the original CFE 223. That makes CFE BLK ideal for small cartridges such as the .17 Hornet and .221 Fireball. The original CFE 223 propellant was formulated for reduced copper fouling (“CFE” in the name refers to “Copper Fouling Eraser”). New CFE BLK shares this reduced fouling technology which was developed originally for the U.S. military. Many of our Forum members have tried CFE 223 and confirmed that is performs “as advertised” — with less copper fouling that most other propellants. That’s a big benefit for varmint shooters, who may put hundreds of rounds through a barrel in a single day on the varmint fields.
Optimized for the .300 AAC Blackout cartridge, CFE BLK works great for .300 Blackout loads in AR-type rifles throughout the range of bullet weights. Moreover, CFE BLK is perfect for subsonic, reduced loads. In addition, Hodgdon reports that CFE BLK performs superbly in many smaller-capacity cartridges, in particular varmint cartridges such as the .17 Hornet, .17 Ackley Hornet, .218 Bee, .221 Fireball. CFE BLK is also well-suited for the 6.8 Remington SPC and the 7.62X39 Russian cartridge.
CFE BLK Meters Well and Burns Clean
CFE BLK is a spherical (ball) powder. Hodgdon reports the CFE BLK meters well, allowing reloaders to throw very consistent charges every time: “This fine powder meters like a dream and leaves no copper residue, extending accuracy for longer shooting periods, and making clean-up quick and easy.”
When doing load development for any rifle, it’s nice to be able to shoot from the bench with a stable front pedestal rest. Unfortunately, rifles with narrow fore-ends and ARs with tubular handguards can be somewhat wobbly on front bags. The solution is to attach a forward bag-rider to your rifle. This provides a nice, wide and flat base that sits securely in a benchrest-style front sandbag. A wide bag-rider helps prevent the gun from rocking, steadies your aim, and improves tracking. If you’re handy with tools, you can craft your own bag-rider from metal, wood, or Delrin, but there’s an easier option. Whidden Gunworks offers a nicely-engineered “bolt-on” front plate that will enhance the bench-rested accuracy of any rifle with an accessory rail on the forearm.
The Whidden Track Plate fits securely in the forearm accessory rail on prone, cross-the-course, and Palma rifles. These guns typically have a narrow and/or rounded fore-end so they rock and wobble when used with a front pedestal rest. The TrackPlate cures that. Once installed it provides a rock-solid, 2.9″-wide platform that mates perfectly with a benchrest-type front sandbag. This gives sling-shooters maximum stability when testing loads or zeroing their sights or scope. Plus you can now shoot F-Class competitively with a prone gun.
The Track Plate is light-weight, has catamaran-style runners to aid tracking and prevent rocking, and can be easily stowed in a range bag. The machined aluminum Track Plate fits BOTH Anschutz-style and American-style recessed forearm rails.
The Track Plate is available from Whidden Gunworks for $40.99 or from Champion’s Choice for $40.00 (item W29P). Plate designer (and National LR Rifle Champion) John Whidden says: “The Plate is great for any rifle with a rail whether it ís smallbore, centerfire, or an air gun. Now you can try F-Class with your favorite prone rifle: the Plate has a perfect low-drag finish for riding a rest or sandbags and is competition legal in all dimensions.”
Front Bag-Rider for AR-15s from EGW
Similar to the Whidden Track Plate is a 3″-wide Delrin bag-rider from Evolution Gun Works (EGW). This was developed expressly to fit the fore-ends of AR15-type rifles with round float tubes. The EGW front bag-rider attaches to a front sling swivel stud anchor. That allows it to mount as easily as a Harris bipod — no rail needed! Just unscrew the swivel stud, put the front bag-rider in place and attach one hex-head machine screw. The front bag-rider is contoured to match the handguard profile so it fits securely with no wobble. Overall, it is a slick system. Front and rear bag-riders can be attached in a couple of minutes. The Delrin blocks slide easily in the bags and make the gun ultra-stable. The gun tracks straight back. The front bag-rider comes in two (2) variants, a $39.99 radiused version (item 32141) that attaches via swivel stud, and a $49.99 version (item 32143) that mounts via a Picatinny-style rail.
EGW AR Front Bag-Rider System
EGW Picatinny Rail-Attached Front Bag-Rider
EGW Rear Bag-Rider for AR Buttstocks
EGW also offers a REAR bag-rider that attaches via the sling swivel anchor. The EGW AR Rear Bag-Rider accessory (item 32142), designed to work with A2-style buttstocks, sells separately for $39.99. This rear bag-rider provides a longer, straight “keel” that works very well in rear sandbags, giving the rifle more stability, and improving the tracking.
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There’s a new long-range precision tactical rifle from Ritter & Stark (R&S) of Austria. The new SX-1 Modular Tactical Rifle (MTR) is designed to allow rapid barrel changes for three chamberings: .308 Winchester, .300 Winchester Magnum, and .338 Lapua Magnum.
Notably, the scope rail is mounted on the barrel itself, and the bolt locks directly into the barrel. This patented system allows scope, rail, and barrel to be swapped out as one integrated assembly, which should definitely help maintain zero when barrels are exchanged.
Ritter & Stark explains: “The MIL-STD 1913 Picatinny rail is installed directly on the barrel, allowing barrel interchangeability with pre-set scopes for no shift of impact when changing calibers. Easily and quickly done in the field, the patented caliber conversion system allows the barrel to be precisely positioned in the machined aluminum receiver with a greater area of contact allowing for more stability. The bolt is locked directly into the barrel breech[.]”
Video Shows Barrel Swap System, and Bolt Locking in Barrel Breech:
CNC-Controlled Rifling Process
Ritter & Stark states: “The rifling is processed in a CNC-controlled electrochemical machine. This avoids the transmission of thermal effects and mechanical stress to the material. Furthermore, this process allows us to produce barrels with unique uniformity and within tolerance zones that were not possible in a serial production before.” This is very interesting technology, and we’d like to learn more about it.
Accuracy Guarantee and Barrel Life Guarantee
Apparently the CNC-controlled rifling process works well as Ritter & Stark guarantees that its barrels maintain accuracy for a long time. The Austrian company states: “Our barrels are guaranteed to at least 5,000 rounds for .308 Win and .338 LM, and 2,000 rounds for .300 WM before noticing any degradation in accuracy.” That kind of claim certainly invites a long-term test. Who’s got enough ammo? Ritter & Stark also claims that “every rifle we manufacture can achieve 0.5 MOA 3-round groups or better with factory match-grade ammunition.”
The Ritter & Stark SX-1 MTR is designed for adaptability. It will accept third-party Rem 700-compatible triggers as well as a variety of AR-type grips. In addition, the SX-1, in standard configuration, will accept other manufacturers’ AI, SR25, or AR10 magazines. The rifle can also accept other buttstock assemblies compatible with Ritter & Stark’s folding mechanism which, interestingly, can be set to fold to either side.
Product Tip from EdLongrange. We welcome reader submissions.
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Can a human, with a sling, shoot as well as a mechanical rest? The answer is “yes” (at least once in a great while) IF that sling shooter can deliver a record-breaking performance. Here’s an interesting tale of man vs. machine from our archives…
The USAMU posed an interesting challenge — could one of their shooters match the performance of a mechanical rest? Who would win in this battle between man and machine? You might just be surprised. At 600 yards, with an AR-platform rifle, the results can be remarkably close, based on targets provided by the USAMU. When clamped in a test rig, a USAMU M16A2 produced a 200-18X group with handloads. The USAMU says this was “one of our better 20-shot groups at 600 yards, testing ammo from a machine rest”. Can a human do better?
Remarkably, a human soldier came very close to matching the group shot from the machine rest. The photo below shows a 20-shot group shot by a USAMU marksman with sling and iron sights, using USAMU-loaded ammunition. The score, 200-16X, was nearly the same. As you can see, the USAMU rifleman didn’t give up much to the machine rest, even at 600 yards!
In fairness, this was no ordinary human performance. The 200-16X score was a new National Record set in December, 1994. This was fired by PFC Coleman in an Interservice Match at Okeechobee, Florida. Brilliant Performance.
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If you’ve been following the tactical message boards, you’ll hear a lot of buzz about FrogLube CLP. Among the zillions of gun cleaner/lubes on the market, FrogLube stands out for its ability to work well even in challenging environments. Intended for U.S. Navy SEAL operators’ use in extreme environments, FrogLube was developed by Larry Lasky (Captain, USN retired), a former Navy SEAL officer. FrogLube’s blend of ingredients has been extensively field tested. The makers of FrogLube claim that fouling is dramatically reduced in FrogLube-treated firearms. FrogLube is a decent carbon-cutter and it also provides protection against rust and corrosion (though there are better rust preventers on the market, such as Eezox).
NOTE: Don’t expect FrogLube to remove copper fouling in the barrel — you’ll need a real copper solvent, such as Montana X-Treme. Overall, though, as a general purpose CLP, FrogLube performs well.
I was introduced to this product by a Sig armorer. I tried it. I loved it. It works. Period. Just like everyone else is saying here. Here is my break down of it as a CLP. The “C”: I have found that putting it on warm metal makes it work great…just like they say. I rub the paste on, let it sit and penetrate. A few minutes later….wipe it off. Clean enough to eat on. I even tried it on my mountain bike chain and components after running out of degreaser. Worked better than anything I have ever tried. The “L”: Once you use it on the parts you will notice it’s still there, having saturated the parts. Great for lube and goes a long way. The “P”: I hunt waterfowl in very rugged and sloppy conditions. The thing about this product is that when they say it saturates the metal, it truly does. Great protective features. It’s still on there and after all that moisture not speck of rust anywhere, unlike even the best of of other CLPs. — J. Zabick
Crazy Good — This stuff is amazing. I use it on my knives, razors and, of course, guns. It smells great, leaves no oily residue and cleans like nothing else I have used. Get the paste and the oil because sometimes the oil is called for and sometimes you need the paste. Can’t recommend it enough. I have already ordered more. — K. Chariton
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Thinking of combining rifle and pistol powder in a blended duplex load? Well think again. If you want to keep all your fingers, stick with factory powders and established loads at safe pressures. Here’s what can happen with a duplex load composed of both rifle and pistol powders. This catastrophic kaboom of an AR rifle took place at the Phoenix (AZ) Rod & Gun Club (PRGC) range. The photos, first posted on the ArizonaShooting.com forum, show how the AR blew up, ruining the bolt carrier, splitting the upper receiver, blowing out the Cavalry Arms polymer lower, and actually detaching the barrel.
Another shooter, who was nearby when the Kaboom occurred, reported: “I was standing 10 feet behind [the shooter], loading mags. The shot was no different than any other shots. I only looked up because the RO was yelling for assistance.”
Obstructed Barrel? Probably Not: “The target showed four hits — the fourth round Kaboomed the rifle. [If there was an obstructed barrel only three holes should be on the target.] A piece of the exploded cartridge is still in the chamber of the barrel. The barrel extension split into three major pieces with smaller pieces cutting the left inside forearm.”
Suspected Cause? “It was a combination of rifle and pistol powder. The rest of the batch was pulled and there were apparently 3-4 other rounds with mixed loads.” It has been reported that these were commercial .223 Rem reloads.
What Happened to the Operator? “The shooter is fine. He got whacked in the face with the charging handle, giving him a fat lip. Minor cuts on his face. His wrist got fragged with carbon fiber/free float tube remains, which were embedded in his skin for a few weeks.”
Parts Ruined: Upper receiver, Cav Arms MK2 polymer lower receiver, Bolt Carrier Group (total loss), forearm, barrel, gas tube, gas block, muzzle brake, mag release, bolt release, custom trigger and take-down pins. Also charging handle is bent and trigger group sustained some damage.
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