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?” He wanted an honest, well-informed answer, not just sales pitches. 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.
Geissele Automatics manufactures a line of two-stage triggers favored by top Service Rifle, High Power, and 3-Gun shooters. Geissele now offers a variety of trigger models for both large-pin and small-pin lowers, with pull weights from 1.8 lbs to 6.0 lbs. You select the Geissele trigger with the appropriate first and second stage pull for your discipline (refer to chart below for trigger model specs).
Video Shows Geiselle Trigger Installation in AR15
Our friend Gavin Gear of UltimateReloader.com has crafted a video showing how to install a Geissele National Match Trigger in an AR15. This video covers installation of the trigger assembly, the trigger guard, the safety selector lever assembly, and the pistol grip.
AR15 Trigger Installation Video
Follow-Up Video for AR10 Trigger Install
Gavin recently released a follow-up video which covers the installation of a Geissele Super Dynamic Trigger in an AR10. The procedure is mostly the same as for the AR15, but this video also covers removal of the AR10 factory trigger, so it’s worth watching. You may want to turn the volume down on your computer’s speakers before playback. CLICK HERE for Geissele Trigger Instruction Manual
AR10 Geissele Trigger Installation
Share the post "How to Install Geissele Triggers in AR15s and AR10s"
Here is Ernie Bishop’s pride and joy, a specialty pistol nicknamed “Batman” because the black carbon-fiber stock looks like the Batmobile. This is one sophisticated handgun. Complete with scope, the Batman pistol weighs under 7.5 pounds, thanks to the ultra-light stock. The carbon stock is 6 inches wide at the fore-end, yet weighs just one pound. Ernie tells us: “This gun shoots amazing and is easy to shoot especially with my SEB MAX Rest.” Ernie adds, “The gun will soon also have a field-usable rear-grip stock so I can shoot it prone from a bipod as well.”
The Batman pistol is chambered for the 6mm “Long Dasher”, a 6mm 40°-shouldered variant of the 6.5×47 Lapua. Ernie loads Berger 105gr Hybrid bullets pushed by Hodgdon H-4350 powder.
The gun, crafted by Eric Wallance of Nawaka Firearms, features an XP-100 action, Jewell trigger, and 15″-long, Brux 1:8″-twist barrel with aluminum muzzle brake. Interestingly, this gun does not have a traditional recoil lug. Instead, gunsmith Wallace milled out a lug from the bottom of the XP-100 action to save weight. On top of the action, the rig carries a Sightron Inc S-III 6-24X56mm scope in Kelbly rings on a custom +20 MOA rail.
Long Dasher Wildcat
Shown at right is a “Long Dasher” 40° wildcat created by Forum member Sunbuilder. This is very similar to Ernie Bishop’s chambering, though there may be small variations related to reamer design (such as freebore). Sunbuilder’s 6-6.5×47 Improved (aka “Long Dasher”) reamer was made by Dave Kiff of Pacific, Tool & Gauge. This wildcat cartridge adds about 2.0 grains capacity to the 6.5×47 necked down to 6mm. The case certainly is impressive with that 40° shoulder. We’re just waiting for the tactical guys to starting run this improved cartridge with its original 6.5mm bore.
Here are three FIVE-shot groups at 500 yards, shot by Ernie’s Batman pistol:
Share the post "Ernie’s Got A Gun… the “Batman” Benchrest Pistol"
With barrels, one wonders “Can a little more length provide a meaningful velocity gain?” To answer that question, Rifleshooter.com performed an interesting test, cutting a .308 Win barrel from 28″ all the way down to 16.5″. The cuts were made in one-inch intervals with a rotary saw. At each cut length, velocity was measured with a Magnetospeed chronograph. To make the test even more interesting, four different types of .308 Win factory ammunition were chronographed at each barrel length.
Test Barrel Lost 22.7 FPS Per Inch (.308 Win Chambering)
How much velocity do you think was lost, on average, for each 1″ reduction in barrel length? The answer may surprise you. With a barrel reduction from 28″ to 16.5″, the average speed loss of the four types of .308 ammo was 261 fps total. That works out to an average loss of 22.7 fps per inch. This chart shows velocity changes for all four ammo varieties:
Summary of Findings: The average velocity loss per inch, for all four ammo types combined, was 22.7 FPS. By ammo type, the average loss per inch was: 24.6 (Win 147 FMJ), 22.8 (IMI 150 FMJ), 20.9 (Fed GMM 168gr), and 22.5 (Win 180PP).
Interestingly, these numbers jive pretty well with estimates found in reloading manuals. The testers observed: “The Berger Reloading manual says for the 308 Winchester, ‘muzzle velocity will increase (or decrease) by approximately 20 fps per inch from a standard 24″ barrel’.”
How the Test Was Done
The testers described their procedure as follows: “Ballistic data was gathered using a Magnetospeed barrel mounted ballistic chronograph. At each barrel length, the rifle was fired from a front rest with rear bags, with five rounds of each type of ammunition. Average velocity and standard deviation were logged for each round. Since we would be gathering data on 52 different barrel length and ammunition combinations and would not be crowning the barrel after each cut, we decided to eliminate gathering data on group sizes. Once data was gathered for each cartridge at a given barrel length, the rifle was cleared and the bolt was removed. The barrel was cut off using a cold saw. The test protocol was repeated for the next length. Temperature was 47° F.”
CLICK HERE to Read the Rifleshooter.com Test. This includes detailed charts with inch-by-inch velocity numbers, multiple line charts, and complete data sets for each type of ammo. Rifleshooter.com also offers ballistics graphs showing trajectories with different barrel lengths. All in all, this was a very thorough test by the folks at RifleShooter.com.
Much Different Results with 6mmBR and a Longer Barrel
The results from Rifleshooter.com’s .308 barrel cut-down test are quite different than the results we recorded some years ago with a barrel chambered for the 6mmBR cartridge. When we cut our 6mmBR barrel down from 33″ to 28″, we only lost about 8 FPS per inch. Obviously this is a different cartridge type, but also our 6mmBR barrel end length was 5″ longer than Rifleshooter.com’s .308 Win start length. Velocity loss can be more extreme with shorter barrel lengths (and bigger cartridges). Powder burn rates can also make a difference.
Share the post ".308 Win Barrel Chop Test: How Velocity Changes with Length"
You probably know by now that David Tubb has introduced a new two-stage trigger for Remington 700 rifles, the Model T7T. Priced at $385.00, the new T7T Trigger is a true two-stage design: first and second stages are independently adjustable for both weight and feel. Overall (combined stage) trigger pull weight can be adjusted from just under 1 pound to slightly over 3.5 pounds.
If you are interested in the 7ZT, watch these two videos. The first shows how to adjust pull-weights for both stages. The second video shows how to modify your stock to provide clearance for the T7T.
This video shows how to adjust the new Tubb T7T two-stage trigger for Remington 700s:
The new T7T is a quality product. We’ve received good feedback from “early adopters” who tell us the two-stage function works well. While installation of the T7T may require minor modifications to your action, most gun owners with basic mechanical skills can install the T7T by themselves. The T7T is made using stainless steel and aluminum for maximum corrosion resistance. Note, installation of the T7T trigger (either Right-Hand or Left-Hand) also requires a companion T7T bolt release, offered by DavidTubb.com for $10.00.
This video shows how to modify your stock to fit the T7T trigger:
Share the post "Tubb T7T Two-Stage Trigger for Remington-Type Actions"
Are you trying to decide what components to use for your next F-Class build, or are you looking to upgrade your current rig? Wonder what the “big dogs” in the sport have selected as their hardware? Here’s what United States F-Open team members are using. The most popular chambering is the .284 Winchester, followed by the 7mm Walker (a 40° .284 Winchester Improved). Kelbly and BAT actions are the most popular, and nearly all team members are using cut-rifled barrels. A wide variety of stocks are used, with PR&T holding a slight edge over second-place McMillan.
Most shooters know Carl Bernosky as a 10-time National High Power Rifle champion. But you may not realize that Carl is also a very talented stock-maker and rifle-builder. Carl crafts a wide variety of wood and wood laminate stocks for competition as well as hunting. He also crafts many stocks for Alex Sitman of Master Class Stocks.
Master Class Low-Profile F-Open Stock
Here is a new Master Class Low-Profile F-Open Stock crafted by Carl Bernosky. It is made from a Cherry/Maple wood laminate. This design features a railed fore-end along with a flat, parallel toe for improved tracking and stability on the bags. The front section of the fore-arm has a low profile. This allows the barrel bore axis to ride lower. That helps reduce hop and helps the gun recoil straight back. For more information on this low-profile F-Open stock design, visit Carl Bernosky’s Facebook Page and MasterClassStocks.com.
Note that the stock maintains full depth under the action and quite a few inches forward of the action. This smart design feature is very important. We have seen other low-profile stock designs that can flex or “hinge” forward of the action because there’s not enough wood material there. In fact, the only part of the stock that needs a cut-down profile is the front 10″ or so, where the stock actually rides the front bag.
This particular stock features a “pop-off” magnetic cheekpiece, as well as a buttplate that adjusts for Length of Pull (LOP) via spacers. The action is by Pierce Engineering. This and other Master Class Stock designs can be customized with other features on request.
Share the post "Master Class Low-Profile F-Open Stock by Bernosky"
We’re starting to see barrel tuners employed in more competitive disciplines than ever — from 100 yards to 1000 yards. And even some varmint hunters are employing tuners or tuner/brakes now. This allows them to dial in accuracy with different loads (when shooting hundreds of rounds in a weekend). Here’s a quick over-view of the potential benefits of tuners.
Some people love tuners and others hate them. I use them on my rifles and I’ve had more than one person ask me why on earth I would put one of those things on my barrel. I’ve even had a national long range champion tell me to unscrew it and throw it into Lake Erie on my next trip to the pits at Camp Perry. However, there are other shooters that swear by them and have many match wins to back it up.
It’s an indisputable fact that tuners do have an effect on a rifle’s accuracy, however how much is somewhat open for debate. The large heavy target barrels that we use for benchrest or F-class may not be affected as much by a tuner as a lighter weight sporter type barrel. Each barrel that I’ve installed a tuner on not only showed improvement in accuracy but also displayed a wider load window. The increased accuracy is because of the ability to adjust the tuner to the load, however I believe the wider load window is due to the added weight of the tuner slowing down the barrel vibrations. These are both very important aspects of having a very accurate rifle.
While better accuracy and a wider load window are two areas of improvement, I believe the most important feature of a tuner is the ability to adjust the tune during the middle of a match. This is especially important during matches where you must load all your ammo earlier and cannot make adjustments to the load during the match. If you happen to miss the load, instead of having to deal with a gun that isn’t shooting you can make an adjustment to the tuner and hopefully improve the accuracy of the rifle.
While I’ve laid out several ways that a tuner can help, there are also a few ways that tuners can cause problems. They add weight so if you are shooting a discipline that has weight limits on the rifle, you may not be able to install a tuner and still make weight. Sometimes, a barrel just doesn’t show improvement with a tuner installed. These are few and far between, but it is something to consider. If you make an adjustment to the tuner in a match, you need to make sure you move it in the right direction. Adjusting a tuner in the wrong direction can cause very large groups. And finally, if they aren’t tightened properly, tuners can come loose during firing which will cause a lot of problems as well.
As you can see, tuners have both positive and negative aspects. In my personal experience, the positives far outweigh the negatives so I will continue to use them on all of my competitive rifles. If you’ve been thinking about installing a tuner, hopefully some of the information that I’ve presented will help you make an informed decision.
Share the post "Tuner Basics: Guide to Selection and Use of Barrel Tuners"
What do you get when you cut a 6.5 Creedmoor-chambered barrel down to just over 16 inches? A lot more velocity than you might think. Our friends at Rifleshooter.com recently did a barrel cut-down test with 6.5 Creedmoor test rifle, shortening the barrel from 27 to 16.1 inches in one-inch increments. Surprisingly, with a 142gr Sierra MK, the total velocity loss (as measured with a Magnetospeed) was just 158 FPS, an average of 14.4 FPS per inch of barrel length. With the lighter 120gr A-Max bullet, the total velocity loss was 233 FPS, or 21.8 FPS average loss per inch of barrel.
Five (5) rounds of each type of cartridge were fired at each barrel length and the velocity data was recorded with a MagnetoSpeed V3 barrel-mounted chronograph. The rifle was then cleared and the barrel was cut back one inch at a time from 27″ to just over 16″. NOTE: During this winter test, the air temperature was a very chilly 23° F. One would expect higher velocities across the board had the outside temperature been higher.
The photo below shows how the barrel was cut down, inch-by-inch, using a rotary saw. The barrel was pre-scored at inch intervals. As the main purpose of the test was to measure velocity (not accuracy) the testers did not attempt to create perfect crowns.
6.5 Creedmoor vs. Other Mid-Sized 6.5mm Cartridges
The 6.5 Creedmoor is a very popular cartridge with the tactical and PRS crowd. This mid-size cartridge offers good ballistics, with less recoil than a .308 Winchester. There’s an excellent selection of 6.5mm bullets, and many powder choices for this cartridge. When compared to the very accurate 6.5×47 Lapua cartridge, the 6.5 Creedmoor offers similar performance with less expensive brass. For a tactical shooter who must sometimes leave brass on the ground, brass cost is a factor to consider. Here’s a selection of various 6.5 mm mid-sized cartridges. Left to right are: 6.5 Grendel, 6.5×47 Lapua, 6.5 Creedmoor with 120gr A-Max, 6.5 Creedmoor with 142gr Sierra MK, and .260 Remington.
When asked to compare the 6.5 Creedmoor to the 6.5×47 Lapua, Rifleshooter.com’s editor stated: “If you don’t hand load, or are new to precision rifle shooting, get a 6.5 Creedmoor. If you shoot a lot, reload, have more disposable income, and like more esoteric cartridges, get a 6.5×47 Lapua. I am a big fan of the 6.5×47 Lapua. In my personal experience, the 6.5×47 Lapua seems to be slightly more accurate than the 6.5 Creedmoor. I attribute this to the quality of Lapua brass.”
Share the post "6.5 Creedmoor — Barrel Cut-Down Velocity Tests"
Production wood rifle stocks, both laminates and hardwoods, are commonly made with stock duplicating machines. Stock duplicators allow a stock-maker to copy a master design faithfully and efficiently. The video below, from Colorado rifle-maker Michael Cuypers, shows a stock duplicator (in automatic mode) cutting a piece of Turkish Walnut, for a mauser 98. This machine rotates the blank while a spinning vertical cutting head shapes and trims the blank. This duplicator manually tracks the shape/profile of the master blank. To make another stock, this process needs to be repeated, with the master in place. For more information about this duplicating machine, visit www.riflebuilders.com.
Watch Stock Duplicator in Progress
Future Technology: We are starting to see stocks made with CNC milling machines that cut stock profiles based on three-dimensional scans of master stock designs. However, the traditional mechanical duplicator process in the video is still most commonly used by most of today’s stock-makers.
Turkish Walnut — Where to Get a Beautiful Blank
The Bijou Creek video above shows a Turkish Walnut stock being roughed out. Turkish Walnut is some of the most beautifully figured wood available — but it can be pricy. If you are looking for this kind of ultra-high-grade wood, it makes sense to shop carefully. You’ll find a wide selection of Turkish Walnut blanks at the HunterBid.com website. Hundreds of selections are available at auction. Prices start as low as $150.00. The finest blanks sell for $1,000 or more. New blank selections are added to the website every other day. HunterBid.com is run by Chiron Inc., which is 100% owned by the Ergin family who are of Turkish origin. Chiron maintains warehouses in Dover, NH and Istanbul, Turkey.
Video find by Boyd Allen. We welcome reader submissions.
Share the post "Watch Stock Duplicator Machine in Action"
4140, 4150, 316, 17-4, 6061, 7075-T6 — What is the significance of these numbers? No, they’re not winning lottery numbers. These are all designations for metals commonly used in firearm and barrel construction. 4140 and 4150 are carbon steels, with 4150 often used in mil-spec AR15 barrels. 316 and 17-4 are grades of stainless steel. 316 is “marine grade” stainless, while 17-4 has 17% chromium and 4% nickel. 17-4 is a harder steel used in barrels and receivers. 6061 and 7075-T6 are aluminum alloys. 6061 is “aircraft grade” aluminum, often used for rings and trigger guards, while 7075-T6 is a much stronger, heat-treated aluminum commonly used in AR15 uppers.
You can learn about all these metals (and more) in the online archives of RifleShooter magazine.
Written by Patrick Sweeney, RifleShooter’s Guide to Gun Metal summarizes the primary types of steel and aluminum used in gun and barrel construction. Sweeney explains the nomenclature used to define metal types, and he outlines the salient properties of various steel and aluminum alloys. This is a useful resource for anyone selecting components or building rifles. We recommend you print out the page, or at least bookmark it.
Metals by the Number
The number system for steel classification came from the auto industry. Sweeney explains: “The Society of Automotive Engineers uses a simple designating system, the four numbers you see bandied about in gun articles. Numbers such as 1060, 4140 or 5150 all designate how much of what [elements are] in them. The first number is what class—carbon, nickel, chromium, and so forth. The next three numbers [list other elements in the alloy]. 4140, also known as ordnance steel, was one of the early high-alloy steels. It has about 1 percent chromium, 0.25 percent molybdenum, 0.4 percent carbon, 1 percent manganese, around 0.2 percent silicon and no more than 0.035 percent phosphorus and no more than 0.04 percent sulphur. That leaves most of it, 94.25 percent, iron.”
Numbers are also used to differentiate different types of aluminum alloys. Sweeny writes: “Aluminum is used in firearms in two alloys: 7075 and 6061. 6061 is commonly referred to as ‘aircraft aluminum’ and has trace amounts of silicon, copper, manganese, molybdenum and zinc. 7075 is a much stronger alloy and has markedly larger amounts of copper, manganese, chromium and zinc.” 7075 Aluminum has significantly better corrosion resistance, and that’s why it is used for AR receivers. The “T6″ you often see appended to 7075 refers to a heat-treating process.
Aluminum (or “Aluminium” in the UK) is a chemical element in the boron group with symbol Al and atomic number 13. It is a silvery-white, soft, nonmagnetic, ductile metal. Aluminum is the third most abundant element, and the most abundant metal, in the Earth’s crust. (Wikipedia)
To learn more about the metals used in your firearms’ barrels, rings, receivers, and internal parts, read Sweeney’s article in RifleShooterMag.com. Taking the time to read the article from start to finish will expand your knowledge of metal properties and how metals are chosen by manufacturers and gunsmiths. CLICK to Read Guide to Gun Metal.
Story Tip by EdLongrange. We welcome reader submissions. Aluminum Alloy chart courtesy AluminiumDesign.net.
Share the post "Metal Properties Revealed in ‘Guide to Gun Metal’"
Can you list all the serious problems that excessive headspace can cause? For that matter, could you even explain what, exactly, is meant by the term “headspace”? If not, you should watch this instructional video from Brownells. This video defines the term “headspace”, explains why proper headspacing is critically important, and illustrates how headspace gauges work.
Headspace is a measurement from the bolt-face to a point in the chamber. This point of measurement will vary based on the type of cartridge. Improper headspace, either excessive or (conversely) under SAAMI specifications, can cause a variety of problems, many serious.
Problems Caused by Too Much Headspace
Excessive headspace issues can include: light primer strikes, failure to fire, bulged/blown cases, case separations, split shoulders, or unseated primers after firing. Case ruptures caused by excessive headspace can lead to catastrophic failures causing serious injury. That is why headspace is such an important measurement.
Problems Cause by Too Little Headspace
Insufficent (or excessively tight) headspace can prevent the firearm from going into battery, resulting in failure to fire or deformation of the cartridge case. Various feeding and functioning problems can be caused by cases with too little headspace, even if a round can be chambered (with effort).
Share the post "Headspace 101: What You Need to Know"
Last summer we published our comprehensive 6.5×47 Lapua Cartridge Guide, researched by the 6.5 Guys. In case you’ve been wondering what kind of accuracy is possible for a tactical-type rifle chambered for this mid-sized cartridge, check out this tack-driver built by gunsmith Ryan Pierce. That’s a mighty impressive 0.206″ five-shot group fired with Berger 140gr Hybrids using a Brux cut-rifled barrel. The powder was Hodgdon H4350, a very good choice for this cartridge.
Ryan reports: “Here is a 6.5×47 I built for a customer. It features a trued Rem 700 action, Brux 1:8″ Rem varmint-contour barrel, Mcmillan thumbhole stock, Surgeon bottom metal, and 3-port muzzle brake. The customer’s preferred load is the same that has worked in the last couple dozen 6.5x47s I’ve built: 41.1-41.3 grains of H4350 with 140 hybrids .050″ off the lands. This should run about 2810-2815 fps from a 26″ barrel. The 3.128″ refers to length of a loaded round from the base to ogive including the Hornady ogive comparator tool.”
Share the post "6.5×47 Lapua — Accuracy to Spare for Tactical Applications"
Brownells recently reviewed some interesting new products including Howa Barreled Actions and a low-profile titanium gas block for AR-platform rifles. We really like the Howa Barreled Actions as the basis of a varmint or hunting rifle build. The actions are smooth and the Howa-supplied, adjustable HACT 2-stage trigger is excellent. Brownells will stock these barreled actions in a wide range of calibers and barrel profiles (including some with threaded muzzles for brakes or suppressors).
Watch Brownells NEW PRODUCT Review 3/11/2016:
Starting at $407.00, Howa Barreled Actions include hammer-forged barrel, bottom metal, magazine (internal or DBM), and the HACT 2-stage trigger. The three-position safety allows you to manipulate the bolt with the trigger blocked. These Howa barreled actions, which are drilled and tapped for scope mounts, come in Blue or Cerakote Gray finish in Short, Long, and Mini-Action sizes. The Howa Mini-Action is a great basis for a light, compact small-caliber varminter.
Low-Profile Titanium Gas Block for AR-Platform Rifles
The Battle Arms AR-15 Titanium Gas Block (#100-800-003) provides a very trick, low-profile set-up for an AR “space gun” or 3-Gun rig. Light and strong, the Battle Arms Ti gas block fits underneath almost any handguard. This slim, ultra-lightweight Titanium block helps keep an AR-15 rifle/carbine fast and maneuverable by reducing front-end mass. Brownells price is $99.95.
Share the post "Howa Barreled Actions and Ti Gas Block Reviewed by Brownells"
Readers who have just recently discovered the Daily Bulletin may not realize that AccurateShooter.com has hundreds of reference articles in our archives. These authoritative articles are divided into mutiple categories, so you can easily view stories by topic (such as competition, tactical, rimfire, optics, shooting skills etc.). One of the most popular categories is our Technical Articles Collection. On a handy index page (with thumbnails for every story), you’ll find over 100 articles covering technical and gunsmithing topics. These articles can help you with major projects (such as stock painting), and they can also help you build more accurate ammo. Here are five popular selections from our Technical Articles archive.
Planning to put together an AR-platform rifle? Or are you looking to upgrade your AR with a new barrel, stock, or trigger group? Then you should check out the AR-15 Rifle Build DVD from our friends at UltimateReloader.com. This DVD covers all the details of a custom build, using high-resolution video sequences, and helpful supporting graphics.
In this DVD, Gavin Gear guides you through the entire process including selecting components, acquiring and using the necessary tools, assembly steps and details for each component, and even mounting a scope. Building an AR-15 can be overwhelming, but with the right guidance and help it’s not difficult and is a lot of fun. With this DVD you’ll be able to build your AR-15 with confidence.
Right now, as a New Year’s promotion, the AR-15 Build DVD is on sale for just $9.90 (plus $3.80 shipping/handling). This DVD can pay for itself many times over by showing you how to do your own gunsmithing (and get quality AR components at attractive prices).
Upper: Barrel / Gas Block / Gas Tube
Upper: Handguard Installation:
Share the post "Building an AR-Platform Rifle DVD on Sale"
At the IWA Trade Show in Germany a few years ago, a correspondent for The Firearm Blog interviewed Woody Woodall, who runs Lothar Walther’s USA operation. While many shooters assume that Walther hammer-forges most of its barrels like some other European barrel-makers, in fact Lothar Walther USA uses the button rifling technique for most of its US-made barrels.
In the video below, created for The Firearm Blog, Woodall explains that button rifling involves some extra steps to ensure a good result: “The extra work that goes into it is that you’ve got to make rifling, stress relieve it, and have it come out the right size. And it takes a lot of skill to do that. Lothar Walther invented button rifling in 1925, if a better way of making rifling came out, we’d be glad to go to it.”
Woodall explains that hammer forging is a good method for mass production, but it is costly to set up: “Hammer forging is relatively new, it came out in 1934, but did not come into prominence until the 1950s…. But the cost of [hammer forging] in the world today is getting above what the market will bear for barrels. [Hammer forging] is more complicated. As the hammers hit the barrel the barrel gets longer, but the hammers have to hit uniformly so the barrel [stays] straight. There’s a higher failure rate in that. There’s also some surface delamination that can occur, and some other issues. So if you’re hammer forging, you really have to pay attention to the details. So, it’s like button rifling, only ten times more complicated. It’s for super-high-volume production… The large companies tend to use the hammer forging, intermediate size companies tend to use the buttoning, and craft companies tend to use the cut rifling. All three [methods] can make an equally accurate barrel.”
How well can factory .308 Win ammo perform? Amazingly well it seems. Our friends at Criterion Barrels recently tested some .308 ammo from Creedmoor Sports. This was loaded with Lapua’s 175gr Scenar HPBT bullet. The results speak for themselves. Any time factory ammo can shoot inside quarter-MOA, that’s impressive. This ammo was used in a “Rem/Age” project rifle. That term refers to a Remington action rifle that has been re-barreled with a pre-fit Criterion barrel. The new barrel is secured with a Savage-style barrel nut. Hence the term “Rem/Age” or “Rem-Age”.
Criterion posted: “I think we may have a new favorite factory match load for the nitrided Rem/Age build.” Another reader added: “[Creedmoor’s] 175 Scenar .308 ammunition is top notch.” FYI, this group was shot on our load development target, which you can download for free from our Targets Page.
Why do Criterion barrels shoot so well? One reason is that Criterion’s barrel steel is carefully stress-relieved. In the photo below, Criterion Rack 1A (aka the “Coffin”) has been loaded with barrel blanks — made ready for the stress-relieving process.
Share the post "Criterion Gets Tight Groups with Creedmoor .308 Win Ammo"
Report by Vince Bottomley Victrix Armaments, an Italian company, has developed new technology that could be a major “game-changer” in the world of precision rifles in general, and F-Class in particular. Victrix’s leadership group knows all about excellence — and winning. Giuseppe Valtorta, CEO of Victrix Armaments, is a top competitive shooter who won Gold with his F-TR rifle at the 2015 European F-Class Championships.
A New Breed of F-Class Rifle
Turn back the clock half a century — George Farquharson is happily shooting a modified military rifle with iron sights and sling. He hasn’t even dreamt of F Class…
Benchrest however is beginning to gather momentum. Accuracy seekers are demanding the ultimate in precision engineering. They will go to their favorite gunsmith and, if they’re very lucky, procure one of the new custom actions from Hart or Shilen.
In the last 50 years, what’s changed? Benchrest is still with us but F-Class has emerged as a world discipline and, to some extent, brought new challenges to our accuracy rifle builders. But, whilst the rest of the planet has reveled in the speed and precision of CNC machining, we still love to place our faith in the gunsmith and his trusty old lathe!
But, of course, there is a reason for this. CNC equipment is expensive and geared towards the rapid multiple production of precision parts, whereas the custom gunsmith is dedicated to the ‘one-off’ build.
Also, even with a limited run, CNC does not readily lend itself to chambering our cut- or button-rifled barrels. Good as our barrels are, there are issues that have made CNC machine problematic. Each barrel demands loving care at the hands of our chosen gunsmith – if it is to perform to our expectations.
5-Axis CNC vs Manual Barrel Chambering
What if — What if the whole barrel-fitting and chambering process could be made “CNC compliant” and produce a rifle which would equal (or even exceed) the accepted standard. And do it every time, time after time! Cost could be reduced and also waiting times.
Good as our custom barrels are, they still need to be scrupulously checked — for uniformity of the bore, the lands, the grooves — for straightness, consistency of diameter, and concentricity. This could be achieved, using some pretty sophisticated measuring equipment — but that would be outside the realms of the custom gunsmith.
Even then, how could the barrel be easily accommodated in a CNC five-axis machining center to ensure a set-up for the best possible chamber and threading? Remember, bores are rarely concentric to the outside diameter and seldom straight, so the set-up would need to ensure that any deviation would be in the vertical plane when the barrel is screwed in the action and the chamber-section would need to be exactly aligned.
These are of course the issues faced every day by the custom gunsmith but currently, there are few CNC machines which could easily accommodate this requirement. But yes, there are a few….
Let me introduce you to Victrix, an Italian engineering company with an impressive multi-million euro factory crammed with the very latest in CNC machinery and a state of the art measuring laboratory. They already have a well-established background in the firearms manufacturing industry, at both military and sporting level. Never heard of Victrix? You soon will, for Victrix has chosen the prestigious 2016 IWA Show (Hall 9 – 423) to launch its new range of high-end rifles.
Victrix manufacturing facility in Italy is ‘crammed with the very latest in CNC machinery':
Whilst Victrix initially developed a range of tactical/military firearms — some of which will also be of interest to the sport shooter — the company has now turned its attention to the F-Class discipline. By working with those competing at the highest level of F-Class competition, Victrix has developed a range of “off the shelf” F-Class rifles that are “competition-ready” right out of the box. Incidentally, Victrix have chosen American barrel-maker Benchmark as its exclusive barrel supplier. Victrix has already perfected a way of accurately assessing barrels to adapt them to CNC working, and this is the key to the new project.
Victrix Target Trigger — Adjustable down to an Ounce
Victrix F-Class rifles will feature an advanced, new target trigger engineered by Victrix. This four-lever target trigger boasts an adjustment range of 1 to 2.5 ounces (30 – 70 grams). Another trigger (8 to 21 ounces pull weight), is used for the Victrix tactical rifles.
For its new line of rifles, Victrix have developed its own proprietary actions. These actions employ some interesting ideas. The bolt is three-lug with a 60-degree lift and 105/105/150 degree lug-geometry. Testing verified that this arrangement provided a greater resistance to flexing in the locked position over the more traditional 120/120/120 geometry. This geometry also aids the pick-up and feeding of rounds from a magazine when used in a tactical configuration.
Above is Victrix’s new action. It’s impressive. Multiple configurations are offered: Right Bolt/Left Port, Right Bolt/Right Port and other variations. The action can be fitted with Victrix Target or Tactical trigger.
The action and bolt are machined from 17.4PH stainless steel and then hardened (body 48 Rockwell, bolt 45 Rockwell) and treated with PVD (physical vapor deposition). Finally the actions are coated with chromium nitride and nobium for wear-resistance and smooth operation. Tenon thread is M27x1.5 and of course, tolerances are ‘benchrest’ standard. Picatinny rails are screwed and pinned to the action.
Victrix has certainly done its homework. The company will offer rifles for both F-Open and F-TR classes. Stocks will be offered in a variety of materials: wood, wood-laminate, aluminum, and carbon-fiber. The stocks share a no-nonsense, straight-forward design, specifically for shooting a rested rifle.
Whilst we are focusing on their F-Class rifles, we shouldn’t forget the Victrix tactical range. Although designed with military and police use, they will appeal to anyone who enjoys tactical-style shooting. There is no compromise on quality or accuracy so, expect the same build standard but with stocks CNC’d from 7075 mil-spec aluminum with a hard-anodized coating. The Victrix three-lever tactical trigger adjusts from 8 to 21 ounces (250 – 600 grams).
Victrix has chosen March Scopes UK (IWA Hall 3A – 110) as its business partner in launching the new Victrix F-Class rifles. This was a wise choice, as March Scopes UK proprietor Gary Costello is a former World F-Class Champion. Gary, well-known to F-Class competitors, continues to shoot with the Great Britain Team.
We look forward to taking a closer look at the Victrix F-Class rifles and hope to provide an in-depth range report in the not-too-distant future. Check out the Victrix website at www.Victrixarmaments.com.
Share the post "Victrix Armaments Rifles with Advanced 5-Axis CNC Technology"
Here’s one of the most popular videos from the Daily Bulletin archives. If you’ve ever wondered how a top-flight, custom rifle is built, watch carefully….
This video, produced for the folks at S&S Precision in Denton, Texas, shows a full custom 6.5×47 bench rifle being crafted from start to finish. It is a fantastic video, one of the best precision rifles video you’ll find on YouTube. It shows every aspect of the job — action bedding, chambering, barrel-fitting, muzzle crowning, and stock finishing.
You’ll be amazed at the paint job on this rig — complete with flames and four playing cards: the 6, 5, 4, and 7 of spades. Everyone should take the time to watch this 13-minute video from start to finish, particularly if you are interested in stock painting or precision gunsmithing. And the video has a “happy ending”. This custom 6.5×47 proves to be a real tack-driver, shooting a 0.274″ three-shot group at 400 yards to win “small group” in its first fun match. NOTE: If you have a fast internet connection, we recommend you watch this video in 720p HD.
We’re told that the founder of S&S Precision, the inimitable “Stick” Starks, is retiring from full-time gunsmithing duties. This video is a nice tribute to Stick’s dedication to his craft for so many decades.
Share the post "Great Video Shows Custom 6.5×47 Lapua Rifle Build by S&S"