Scientists at the Oak Ridge National Laboratory (ORNL) have developed a system that uses lasers and fiber optics to measure very small changes (deflections) in a rifle barrel. These deflections are recorded with laser sensors, and then algorithms are used to compute the resultant changes in bullet trajectory. Using computer-calculated trajectories, the digital sighting system’s “virtual” reticle automatically adjusts to compensate for barrel deflection, as well as changing environmental conditions. The microprocessor-controlled digital reticle can adjust to 1/1000th of a Minute of Angle (MOA). That makes it far more precise than any conventional riflescope reticle.
ORNL Barrel Sensor with Compensating Reticle
Shown below is a laboratory prototype of Oak Ridge National Laboratory’s Reticle Compensating Rifle Barrel Reference Sensor. This system precisely measures the deflection of the barrel relative to the sight and then electronically makes the necessary corrections. The system was developed by a team led by Oak Ridge National Laboratory’s Slobodan Rajic, shown in the photo.
The Reticle Compensating Rifle Barrel Reference Sensor takes the guesswork out of shooting by shifting the burden of knowing the relative position between the barrel and the weapon sight axes from the shooter to an electronic sensor. The system precisely measures the deflection of the barrel relative to the sight and then electronically realigns the moving reticle, or crosshairs, with the true position of the barrel, or bore axis.
“When a weapon is sighted in, the aim point and bullet point of impact coincide,” Rajic said. “However, in the field, anything that comes into contact with the barrel can cause perturbation of the barrel and induce errors.”
With modern high-caliber rifles boasting ranges of up to two miles, even very small barrel disruptions can cause a shooter to miss by a wide margin. That makes this technology indispensable from a marksman’s perspective, Rajic said.
From a technological standpoint, the approach is straightforward. ORNL starts with fluted barrels (the flutes play a key role). With the ORNL technology, glass optical fibers are placed into the flutes. The sensor system contains a laser diode that sends a signal beam into the optical fibers parallel to the bore axis of the barrel.
“The optical fibers are designed to split the laser beam twice, sending one beam along the top of the rifle barrel and another light beam along the side of the barrel,” Rajic said. “Thus, we can measure both the vertical and horizontal barrel deflection.”
Through a combination of algorithms, optics and additional sensor inputs, the system can take into account distance and other factors affecting the bullet trajectory. Ultimately, the whole optical/laser/digital system provides the shooter with crosshairs that automatically adjust for conditions in real time.
A Compensating Reticle with 1/1000 MOA Precision
Skeptics of electronic sighting systems have complained that the resolution of a digital rifle-sight is too crude to allow precise aiming. There simply aren’t enough pixels on a viewscreen to allow ultra-precise aiming at long-range targets, shooters have said. In fairness, the existing commercially-available digital rifle sighting systems HAVE been crude — with a lo-rez screens like you might find in a portable GPS.
Well you can forget all that. ORCL has achieved a break-through in digital sighting. The bar has been raised — by an order of magnitude. The resolution of ORNL’s digital, sensor-informed Compensating Reticle is 125 times better than that of traditional target reticles, which can normally be adjusted by one-eighth Minute of Angle (MOA) (at best). Now get this — the ORNL sensor can sense angular displacement and shift the reticle by 1/1,000th of a minute of angle. While this system is expensive, and designed (at this point) for the military, this technology could eventually benefit sport shooters. A decade from now, we would not be surprised if long-range civilian shooters commonly use electronically-enhanced optics, with digital reticles that automatically compensate for bullet drop (and maybe even windage).
ORNL scientists are also working on technology that could yield much more precise and accurate plots of bullet trajectories. We will no longer have to rely on “guesstimated” data inputs, and certain assumptions about bullet drag factors. Rajic and colleagues are developing a laser-based, bullet tracking system that would record plot the bullet’s actual flight path while the bullet is in the air. In other words, this tracking system would be able to plot the bullet’s true trajectory from muzzle to target. That is much differerent than current ballistic “solvers” which merely draw a predicted arc based on muzzle velocity, wind and temp inputs, and a reference BC value.
Oak Ridge National Laboratory is a multi-program science and technology laboratory managed for the U.S. Department of Energy by UT-Battelle, LLC. Over 3000 scientists and engineers at ORNL conduct basic and applied research and development to create scientific knowledge and new technology in key areas of science, energy, the environment, and national security.
NOTE: This article was released in May 2012. That is over TEN YEARS AGO. The items are no longer offered with such pricing.
M1 Garand barreled receivers (item RM1SABRWB) are now available from the CMP for $350.00 plus $12.95 shipping. Combine one of these with an $82.00 walnut M1 Garand replacement stock from Boyds’ Gunstocks and you’ll have a handsome and affordable rig. (But sights, trigger group, op rod, gas system, and other key components must still be acquired.) These are Grade B receivers with “service grade” or “high quality service grade” barrels. The CMP notes that: “Receiver may have minor pitting / frosting above and below below the wood line and has been refinished. Bolt includes: extractor, extractor spring & plunger, ejector, ejector spring and firing pin.”
Get ready for the 7th Annual Shilen Swap Meet. Rain or shine, the Swap Meet will be held from 8:00 am to 3:00 pm on Saturday, April 7th, in the Shilen parking lot (Ennis, TX). The event is open to “all comers” — both buyers and sellers. There are NO fees or costs. Anyone can set up a table or just back their truck up and drop their tailgate. There will be gun stuff everywhere — buy and sell as much as you like. And there will be FREE FOOD — complementary chili, frito pie, water, tea, or coffee.
Shilen does request advanced notice from Swap meet attendees, especially folks selling shooting gear: “Please call (972) 875-5318 if you plan on attending so we can have a rough head count. If you want to put up a table please call, fax or email us and let us know. We will add you to the list of vendors.”
Big Discounts on Barrels
Shilen’s ‘Swap Meet Barrels’ will be BACK. These are first-quality barrels built for customers who requested a specific contour, twist rate, or caliber, but later changed their minds. Shilen let these customers modify their orders, but some of these custom-ordered barrels remain in inventory. These pre-ordered “orphan” barrels will be sold at deeply discounted prices at the Swap Meet. NOTE: All warranties still apply; these are NOT lower quality or factory seconds.
Factory tours will be given. During the morning tours, the drill, ream and rifle machine will be operating. Schedule so far is that factory tours (with RUNNING machines) will be offered at 8:00 am, 8:30 am, 9:00 am, 9:30 am, 10:00 am, 10:30 am, 11:00 am and 11:30 am. Tours will continue in the afternoon, but no machines will run then.
Larry Racine is a respected gunsmith based in New Hampshire. He is also a two-time member of the U.S. Palma Team, and a five-time New Hampshire State Highpower rifle champion. Larry, who runs LPR Gunsmithing, has developed a brilliantly simple means of switching rifle barrels with an ordinary spanner or open-end wrench. With this set-up you can switch barrels in the field in seconds without the need for a barrel vice.
For most barrels, Larry mills a hex with six flats on the end of the barrel. This allows a shooter to change barrels quickly at home or on the line with a simple box-head wrench or a socket wrench. Larry says: “You don’t even have to take the barreled action out of the gun. Just set the buttstock on the ground, between your feet, put a wrench on it, hit it with the palm of your hand — and off comes the barrel.” For barrels fitted with a muzzle brake, Larry has a slightly different system. He mills two flats behind the brake so you can use an open-end wrench to do the job.
With either a hex on the end, or two flats for a brake-equipped rifle, the system works with any medium- to heavy-contour barrel with a muzzle-diameter of at least 0.700″. This will even work for high-power rigs using clamp-on sights or bloop tubes. Larry explains: “A lot of us here in New England use clamp-on front sights. The barrel will be turned to 0.750 for the sight, with the hex on the end. A bloop tube can go right over the end, no problem.”
Larry has used this system over the past few years to win a number of matches. In one 600-yard 3 by 20 prone match, Larry used three different barrels, with three different chamberings, on the same Savage rifle. Larry changed the barrels on the line.
Larry was able to do this because the system has little to no loss of zero from one installation of a given barrel to the next installation of that barrel. This lets the shooter start the match with confidence that the first sighter will be on paper. Larry reports that the simple system works great: “To date we have used this system on Savage, Remington, Winchester, RPA, and Nesika actions.”
Racine’s system is very affordable. If Larry does the chamber work on your barrel he charges $45.00 extra to mill a hex or two flats on your barrel. If you only want the hex or flats done, Larry charges $55.00. For more info, visit LPRGunsmith.com or call Larry at (603) 357-0055.
Magnum Research has released a new semi-auto .22LR rifle, the MLR22AT, that should be good for plinking, walk-around varminting, and rimfire gun games. MSRP for the MLR22AT will be $562. The rifles will start shipping in spring 2012.
The MLR22AT features a .22LR Benz target chamber optimized for semi-automatics. The black anodized receiver is CNC-machined from a 6061-T6 aluminum forging. The MLR22AT has an approximate weight of 4 ¼ lbs, barrel length of 17 inches, and OAL of 35.5 inches. This rifle utilizes the 10/22 trigger group and Ruger 10/22 rotary magazines — that means you have a wide choice of aftermarket upgrades.
The MLR22AT features a lightweight, ambidextrous thumbhole tupperware (polypropylene) stock. The stock material incorporates fiber stiffeners, but we still bet this stock is too flexy. Magnum Research claims the comb is high enough to shoot with optics. We just wish the fore-end was stiffer and came with a sling swivel stud for mounting a Harris bipod. Then this compact rifle would be good for rimfire tactical matches as well.
Graphite-Sleeved Barrel is Light, Stiff, and Runs Cool
The most trick feature on this rifle is the graphite-sleeved bull barrel, a Magnum Research exclusive. The barrel’s patented uni-directional graphite fibers, parallel to the bore axis, produce a lightweight barrel with exceptional stiffness. (Magnum Research claims the barrel has six times the stiffness of steel.) The graphite construction definitely saves weight — this barrel tips the scales at just 13-16 ounces, depending on barrel length. Magnum Research also claims the composite barrel dissipates heat up to 43% faster than steel. Sounds good, but heat isn’t as much of an issue with rimfire barrels, as compared to centerfire tubes.
Here’s a little known fact that may startle most readers, even experienced gunsmiths: your barrel wears out in a matter of seconds. The useful life of a typical match barrel, in terms of actual bullet-in-barrel time, is only a few seconds. How can that be, you ask? Well you need to look at the actual time that bullets spend traveling through the bore during the barrel’s useful life. (Hint: it’s not very long).
Bullet-Time-in-Barrel Calculations
If a bullet flies at 3000 fps, it will pass through a 24″ (two-foot) barrel in 1/1500th of a second. If you have a useful barrel life of 3000 rounds, that would translate to just two seconds of actual bullet-in-barrel operating time.
Ah, but it’s not that simple. Your bullet starts at zero velocity and then accelerates as it passes through the bore, so the projectile’s average velocity is not the same as the 3000 fps muzzle velocity. So how long does a centerfire bullet (with 3000 fps MV) typically stay in the bore? The answer is about .002 seconds. This number was calculated by Varmint Al, who is a really smart engineer dude who worked at the Lawrence Livermore Laboratory, a government think tank that develops neutron bombs, fusion reactors and other simple stuff.
On his Barrel Tuner page, Varmint Al figured out that the amount of time a bullet spends in a barrel during firing is under .002 seconds. Al writes: “The approximate time that it takes a 3300 fps muzzle velocity bullet to exit the barrel, assuming a constant acceleration, is 0.0011 seconds. Actual exit times would be longer since the bullet is not under constant acceleration.”
We’ll use the .002 number for our calculations here, knowing that the exact number depends on barrel length and muzzle velocity. But .002 is a good average that errs, if anything, on the side of more barrel operating life rather than less.
So, if a bullet spends .002 seconds in the barrel during each shot, and you get 3000 rounds of accurate barrel life, how much actual firing time does the barrel deliver before it loses accuracy? That’s simple math: 3000 x .002 seconds = 6 seconds.
Gone in Six Seconds. Want to Cry Now?
Six seconds. That’s how long your barrel actually functions (in terms of bullet-in-barrel shot time) before it “goes south.” Yes, we know some barrels last longer than 3000 rounds. On the other hand, plenty of .243 Win and 6.5-284 barrels lose accuracy in 1500 rounds or less. If your barrel loses accuracy at the 1500-round mark, then it only worked for three seconds! Of course, if you are shooting a “long-lived” .308 Win that goes 5000 rounds before losing accuracy, then you get a whopping TEN seconds of barrel life. Anyway you look at it, a rifle barrel has very little longevity, when you consider actual firing time.
People already lament the high cost of replacing barrels. Now that you know how short-lived barrels really are, you can complain even louder. Of course our analysis does give you even more of an excuse to buy a nice new Bartlein, Krieger, Shilen etc. barrel for that fine rifle of yours.
Smart shooters know the importance of using a quality cleaning rod bore guide when cleaning barrels. The rod guide helps center the rod in the bore, preventing uneven wear on the rifling. Good bore guides also seal off the chamber to prevent solvents and gunk from flowing back into the bolt raceway and trigger housing. While most bore guides are “better than nothing”, the best designs are custom-sized to the chamber and also have a very tight clearance around the rod shaft. This prevents the rod from bowing and from dragging on the critical throat area of your rifle. We use Lucas Rod Guides for many of our rifles. The Lucas two-part design, with a caliber-specific insert, provides a tight fit for the rod.
T.K. Nollan’s Barrel Saver System
While many readers may have seen or used Lucas Rod Guides, T.K. Nollan makes another very high-quality cleaning rod guide that is favored by top benchrest shooters such as Tony Boyer, Dwight Scott, and Dick Wright. If, like many short-range Benchresters, you do a lot of barrel brushing, it may be worth investing in the $135.00 Barrel Saver.
T.K. Nollan’s patent-pending Barrel Saver is a precision-machined system designed to provide maximum protection during barrel cleaning. The Barrel Saver features a double O-ring “fail-safe” seal, and a stainless steel outer tube with straightness held to within .001″. To help ensure optimal alignment, a bushing, custom-sized for your action, precisely centers the outer tube in your action. Models are offered for Hall, Stolle, Grizzly, Farley, Remington, RFD, Nesika Bay, Borden, BAT, Viper and similar 2-lug actions.
Each Nollan Barrel Saver comes with two (2) metal guide tubes, one for brushes and the other for jags. As you can see in the slide show below, these brush/jag tubes run INSIDE the larger diameter guide which slides into the action and chamber. This “tube-within-tube” design, combined with the 0-ring for the chamber, ensures that the cleaning rod stays precisely centered, even if you brush fairly aggressively. While we strongly advocate bore-brushing only in the outward direction, we know some shooters prefer to brush back and forth. If you are a “back and forth” cleaner, you NEED a product like the T.K. Nollan Barrel Saver.
T.K. Nollan Barrel Savers start at $135.00 plus $9.00 shipping for PPC-type chamberings. Custom sizes cost $150.00 plus $9.00 shipping. Each Barrel Saver kit comes complete with two Rod Guide Tubes and spare O-rings. For more info, visit the Barrel Saver website, or contact T.K. Nollan at this address:
TK Tool Co. – Precision Benchrest Tools
tknemail [at] gmail.com
401 South Cimarron St.
Catoosa, OK 74015
(918) 633-2966 (Call before 9:00 PM CST)
German Salazar has found some innovative and smartly-engineered new cleaning accessories that can benefit any shooter who wants to maintain the accuracy of his precious (and expensive) barrels. Here’s German’s report on the new Bore Rider Jags and Bore Rider Brush Guides.
Good Stuff: Bore Rider Barrel Care Productsby German Salazar
We see new bore cleaning solvents introduced with some regularity, but cleaning hardware evolves more slowly. I’ve been using some new jags from Don Leidich’s Bore Rider Barrel Care Products for a few months and am satisfied that they are a genuine improvement over anything else I’ve used. Don began making these items for the black powder cartridge shooters as their cleaning needs are serious and frequent. He has now expanded the line to include popular bore sizes for modern centerfire barrels.
Modern Jags and Brush Guides Made from Acetron Polymer
Don’s Bore Rider enterprise makes jags as well as companion Brush Guides for use with bore brushes. These are all made from Acetron® GP, an acetal polymer material similar to Delrin, but with greater lubricity. Bore Rider Jags and Brush Guides minimize any damage that might occur to the crown when the jag or brush exits the bore. With conventional jags and brushes, when brushing or patching your barrel, the cleaning rod shaft falls to the bottom of the bore as the patch or brush exits. Over time, that can result in excessive wear at the lower edge of the bore (6 O’Clock position) in the last few millimeters on the muzzle end. In extreme cases you can even wear a slight groove in the lip of the crown (i.e. the very end of the rifling at the muzzle). Another advantage of Bore Rider Jags over conventional brass jags is that you don’t get “false positive” green/blue patch colorations from solvent reactions with the metal jag itself (as opposed to actual copper fouling in the barrel).
The Bore Rider Jag has an extra-long shank so that when the patch exits, the Acetron (polymer) shank is the only thing that makes contact with the crown. This way you don’t have a metal rod tip riding over the delicate crown. The Bore Rider Jag shank diameter is also a close fit to the bore to avoid uneven wear. The Brush Guide is an Acetron extension that fits between your brush and the end of the cleaning rod. This extension protects the crown when you brush, allowing you to push the brush completely out of the barrel without dragging metal connections over the edge of the crown. [Editor’s Tip: While the polymer material used in the Bore Rider Jag and Brush Guide is “kinder” to crowns, be sure keep the Acetron shanks clean from small particles and debris. These particles can embed themselves in the polymer. Wipe off the Jags and Brush Guides regularly.]
If protecting your barrel’s crown was all that these items did, that would be enough to merit their use. However, what’s more interesting about the jags is that they are made for a very tight fit in the bore and as a result, they truly get the patch working to scavenge the grooves of all the residue possible. The fit is so tight that Don was concerned that not all patches might work properly, as some extra thick ones might not enter the bore at all on this jag. I’ve used the jags with patches from Sinclair, Bruno’s Pro-Shot and a couple of no-name bags and all have worked flawlessly. Also, the jags are designed so that the segments that hold the patch material can never come in contact with the crown while pulling it back into the barrel. My borescope examination of the barrels shows that the job is getting done right.
Source for Bore Rider Jags and Brush Guides
The .223, .243, .264 and .308-caliber jags sell for $15.00 and the Brush Guides sell for $13.00. Other caliber jags start at $22.00 for jags and $18.00 for Brush Guides. These are threaded and chamfered to fit appropriate Dewey rods. The opposite ends on the brush guides have 8-32 female threads. Customers can buy adapters (from other vendors) to fit other brands of cleaning rods. Don can also customize Jags to fit a customer’s rod specifications if you don’t want to deal with an adapter. Don’s custom made Jags and Brush Guides cost $25 and $18 respectively.
Monitor Barrel Heat with Pocket InfraRed Gauges
You never want to run the barrel of a precision rifle too hot. Excessive barrel heat kills accuracy, increases copper fouling, and can cause rapid barrel throat wear. Over the years people have devised various means to cool their barrels — from electric fans to dunking in tubs of ice water.
But how do you know if your barrel is too hot? Consider a “non-contact” thermometer that reads your barrel’s “infrared signature”. The Kintrex or Actron pocket-sized, non-contact IR thermometers are ideal for shooters at the range or in the prairie dog fields. Both are handy and inexpensive — costing about twenty bucks (on sale).
Pen-Sized Kintrex
Just 3.2″ long, and weighing a mere 1.3 ounces, the waterproof Kintrex IRT0401 (IP67) is small enough to carry in your pocket, and will easily stow in any range bag/box. The unit measures from -67 to 428 °F (-55 to 220 °C). Kintrex is a respected manufacturer that also makes larger hand-held IR thermometers for industrial and shop applications. Priced at just $21.11 on Amazon.com, the tiny Kintrex is one gadget that every serious shooter should have. Given the cost of replacing barrels these days, can you afford NOT to have a temp gauge for your match or varmint barrel?
Actron PocketTherm for just $18.22
The compact Actron CP7875 PocketTherm Infrared Thermometer is on sale right now on Amazon.com for just $18.22. Roughly 4″ x 1.5″ in size, it is slightly larger than the Kintrex, but still small enough to carry in a pocket. It features an angled head and may be easier to hold than the Kintrex for some users. It works instantly with intuitive one-button operation, measuring temp ranges from -27º to 428º F (-33º to 220º C). Rated battery life is 20-25 hours. The backlit display is easy to read. However, you need to place the Actron PocketTherm close to the “target”. Most larger “industrial” spot thermometers (both laser and infrared), have beam ratios from 6:1 to 10:1, allowing them to measure a 1″ circle at 6″-10″. The CP7875 has a 1:1 ratio, so it measures a 10″ circle at 10″ distance. To get an accurate temp on a barrel, you must hold the thermometer within an inch or so. That’s not a big deal when measuring barrel heat, but the beam ratio may limit the usefulness of the PocketTherm for other tasks.
Many shooters expend considerable time and effort to coat their bullets with friction-reducing compounds such as Boron Nitride (HBN), Molybdenum Disulfide (Moly), and Tungsten Disulfide (WS2 or ‘Danzac’). Many of these same shooters believe that coated bullets permit longer strings of fire between barrel cleanings. Also, there is some evidence that coated bullets may extend barrel life (though this remains controversial).
What if you could enjoy all the benefits of coated bullets without the effort? When you think about it, why not apply the anti-friction coating to the barrel itself, rather than the bullets? That is the thinking behind salt-bath nitriding of barrels. This nitriding process creates a very slick, very hard surface coating on the steel in the bore. The coating is only 10-20 microns thick (so it doesn’t cause pressure problems). But that coating is enough to reduce friction, and just possibly, extend useful barrel life.
John Whidden, Camp Perry Long-Range National Champion in 2007, 2008, and 2010, recently had one of his Broughton 6mm match barrels nitrided by Joel Kendrick. Joel does the salt-bath nitriding for MMI TruTec. Whidden reports he “is happy as he can be with the barrel” after the nitriding process. After nitriding, the stainless Broughton 5C barrel was “every bit as accurate as before, and noticeably easier to clean”, according to John. Also, John reports that he did NOT have to change his load after the barrel was nitrided (which left it with a handsome black, semigloss finish). Whidden says, “after cleaning, the barrel takes about 3-4 rounds to settle in… that’s the same as before.” This barrel shot very well before nitriding, and after nitriding, John used it successfully at Camp Perry in the 2009 Wimbleton Cup competition.
Overall, John tells us “Everything looks good. No accuracy loss, and easier cleaning.” He is pleased enough that he has sent more barrels to Joel Kendrick for nitride processing. John also said that he’s heard that nitrided barrels in some of the big caliber rifles, such as the .338 Lapua Magnum, are showing “significantly enhanced” barrel life.
To learn more about salt-bath nitriding for barrels, or to place a processing order with MMI-TruTec, email joelkndrck [at] aol.com, or call Joel at (704) 616-6442. Joel, a past 600-yard Shooter of the Year, is very knowledgeable about both shooting and the nitriding process. He can give you well-informed answers to your questions. Price for nitriding depends on quantity — call Joel for pricing details.
The Reticle Compensating Rifle Barrel Reference Sensor takes the guesswork out of shooting by shifting the burden of knowing the relative position between the barrel and the weapon sight axes from the shooter to an electronic sensor. The system precisely measures the deflection of the barrel relative to the sight and then electronically realigns the moving reticle, or crosshairs, with the true position of the barrel, or bore axis.
Larry Racine is a respected gunsmith based in New Hampshire. He is also a two-time member of the U.S. Palma Team, and a five-time New Hampshire State Highpower rifle champion. Larry, who runs 
Gone in Six Seconds. Want to Cry Now?
The Bore Rider Jag has an extra-long shank so that when the patch exits, the Acetron (polymer) shank is the only thing that makes contact with the crown. This way you don’t have a metal rod tip riding over the delicate crown. The Bore Rider Jag shank diameter is also a close fit to the bore to avoid uneven wear. The Brush Guide is an Acetron extension that fits between your brush and the end of the cleaning rod. This extension protects the crown when you brush, allowing you to push the brush completely out of the barrel without dragging metal connections over the edge of the crown. [Editor’s Tip: While the polymer material used in the Bore Rider Jag and Brush Guide is “kinder” to crowns, be sure keep the Acetron shanks clean from small particles and debris. These particles can embed themselves in the polymer. Wipe off the Jags and Brush Guides regularly.]
Source for Bore Rider Jags and Brush Guides
But how do you know if your barrel is too hot? Consider a “non-contact” thermometer that reads your barrel’s “infrared signature”. The Kintrex or Actron pocket-sized, non-contact IR thermometers are ideal for shooters at the range or in the prairie dog fields. Both are handy and inexpensive — costing about twenty bucks (on sale).
