October 2nd, 2013

Lothar Walther Bi-Metal Barrels Are Lighter, and Shed Heat Better

Less weight plus better heat dissipation — Sound good? Here is an innovative barrel technology that promises worthwhile performance benefits for hunters or match shooters. Lothar Walther (LW) has developed a new bi-metal barrel system that cuts weight dramatically while promising significantly-enhanced heat dissipation.

Walther’s Ultra-Lightweight Barrels combine steel with lightweight alloys. This results in a significant weight reduction without the use of carbon fiber, epoxy binders, or other heat-retaining materials. Beginning as an LW50 stainless blank, the barrel is precision-machined to remove excess weight. An outer casing of light-weight alloys is machined and the two are fitted together without adhesives. Basically you end up with the steel inner barrel inside a larger-diameter fluted aluminum outer barrel (see diagram). This gives you the ‘best of both worlds’ — light weight for ease of carry, and thick diameter for rigidity and enhanced heat dissipation. Near the action, the barrel remains all-steel.

The barrels come pre-chambered in your choice of caliber/cartridge, from .22LR up to .338 Lapua Magnum. Walther chambers the barrel — but a gunsmith is still required to finish the shoulder so that the headspace is set correctly for your action. These barrels are not inexpensive. A typical bi-metal Walther Barrel runs $850.00 – $875.00, for barrel lengths from 22″ to 30″. Threading for a muzzle brake or suppressor (if desired) is normally included in that price.

Lothar Walther ultra lightweight bi-metal barrel

Aluminum thermal conductivityWe haven’t tested one of these bi-metal composite barrels, but the potential for significant weight savings is obvious — aluminum is a lot lighter than steel. What’s more, a metals expert we contacted said that a bi-metal system employing fluted aluminum over steel, if assembled properly, could dissipate heat much better than steel alone (given the same diameter). Stainless steel has a thermal conductivity factor of 16. Aluminum has a thermal conductivity factor of 250.*

Our expert also pointed out that some other composite barrel systems on the market actually increase heat retention because they place insulating materials next to the inner steel barrel. (Carbon, Fiberglass, and Epoxy are all considered “insulating substances” as they have very low thermal conductivity*.) The LW system of aluminum over metal should avoid this mistake, our expert believes. Lothar Walther says: “Unlike solid steel barrels, this barrel sheds heat fast. VERY FAST!”

Half the Weight of Conventional Barrels
How much weight can you save? With a 1.200″ shank diameter and a muzzle diameter of 0.850″, the LW Ultra-Lightweight Barrel is less than half the weight of a standard varmint barrel of the same size. Walther claims its UltraLight Barrel can be “carried for long distances and stand up to heavy firing.” This, LW says, makes these barrels “perfect… for varmint and tactical uses”.

Pre-Chambered Ultra-Lightweight Barrels Available in .22 to .338 Calibers
Lothar Walther offers Ultra-Lightweight barrels in a full range of calibers from .22LR to .338. Each Ultra-Lightweight Barrel comes complete with chamber, crown, and breech threads. These barrels are fluted by the factory. If you order a LW Ultra-Lightweight barrel, Lothar Walter provides the services of a specialist trained in building guns with these barrels. To order one of Lothar Walther’s bi-metal barrels, CLICK HERE or contact Lothar Walthar at the address below:

Lothar Walther Precision Tools, Inc.
3425 Hutchinson Rd. – Cumming, GA 30040
Phone: 770-889-9998 | Fax: 770-889-4919
E-Mail: lotharwalther [at] mindspring.com
Website: www.lothar-walther.com

*Thermal conductivity is the quantity of heat transmitted through a unit thickness in a direction normal to a surface of unit area, due to a unit temperature gradient under steady state conditions. The factor values are based on this formula: W/(m.K) = 0.85984 kcal/(hr.m. °C). Here are thermal conductivty values for common materials: Aluminum, 250; Brass, 109; Steel (Carbon 1%), 45; Stainless Steel, 16; Carbon, 1.7; Brick dense, 1.3; Concrete (medium) 0.7; Epoxy, 0.35; Fiberglass, .04.

Story tip from EdLongRange. We welcome reader submissions.
Permalink Gunsmithing, New Product 6 Comments »
June 5th, 2012

ORNL Builds Reticle-Compensating Sight with Laser Barrel Sensor

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.

Oak Ridge Barrel sensorThe 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.

Permalink - Articles, New Product, Optics 7 Comments »
May 13th, 2012

Lothar Walther UltraLight Barrels — Less Heat, Half the Weight

We’re excited when major barrel-makers offer new technologies that promise worthwhile performance benefits for hunters or match shooters. Lothar Walther (LW) has developed a new bi-metal barrel system that cuts weight dramatically while promising significantly-enhanced heat dissipation.

Walther’s new Ultra-Lightweight Barrels combine steel with lightweight alloys. This results in a significant weight reduction without the use of carbon fiber, epoxy binders, or other heat-retaining materials. Beginning as an LW50 stainless blank, the barrel is precision-machined to remove excess weight. An outer casing of light-weight alloys is machined and the two are fitted together without adhesives. Basically you end up with the steel inner barrel inside a larger-diameter fluted aluminum outer barrel (see diagram). This gives you the ‘best of both worlds’ — light weight for ease of carry, and thick diameter for rigidity and enhanced heat dissipation. Near the action, the barrel remains all-steel.

Lothar Walther ultra lightweight bi-metal barrel

Aluminum thermal conductivityWe haven’t tested one of these bi-metal composite barrels, but the potential for significant weight savings is obvious — aluminum is a lot lighter than steel. What’s more, a metals expert we contacted said that a bi-metal system employing fluted aluminum over steel, if assembled properly, could dissipate heat much better than steel alone (given the same diameter). Stainless steel has a thermal conductivity factor of 16. Aluminum has a thermal conductivity factor of 250.*

Our expert also pointed out that some other composite barrel systems on the market actually increase heat retention because they place insulating materials next to the inner steel barrel. (Carbon, Fiberglass, and Epoxy are all considered “insulating substances” as they have very low thermal conductivity*.) The LW system of aluminum over metal should avoid this mistake, our expert said. Lothar Walther says: “Unlike solid steel barrels, this barrel sheds heat fast. VERY FAST!”

Half the Weight of Conventional Barrels
How much weight can you save? With a 1.200″ shank diameter (except Savage) and a muzzle diameter of 0.850″, the LW Ultra-Lightweight Barrel is less than half the weight of a standard varmint barrel of the same size. Walther claims its UltraLight Barrel can be “carried for long distances and stand up to heavy firing.” This, LW says, makes these barrels “perfect… for varmint and tactical uses”.

Pre-Chambered Ultra-Lightweight Barrels Available in .22 to .338 Calibers
Lothar Walther offers Ultra-Lightweight barrels in a full range of calibers from .22LR to .338. Each Ultra-Lightweight Barrel comes complete with chamber, crown, and breech threads. These barrels are fluted by the factory. If you order a LW Ultra-Lightweight barrel, Lothar Walter provides the services of a specialist trained in building guns with these barrels. To order one of Lothar Walther’s bi-metal barrels, CLICK HERE or contact Lothar Walthar at the address below:

Lothar Walther Precision Tools, Inc.
3425 Hutchinson Rd. – Cumming, GA 30040
Phone: 770-889-9998 | Fax: 770-889-4919
E-Mail: lotharwalther [at] mindspring.com
Website: www.lothar-walther.com

*Thermal conductivity is the quantity of heat transmitted through a unit thickness in a direction normal to a surface of unit area, due to a unit temperature gradient under steady state conditions. The factor values are based on this formula: W/(m.K) = 0.85984 kcal/(hr.m. °C). Here are thermal conductivty values for common materials: Aluminum, 250; Brass, 109; Steel (Carbon 1%), 45; Stainless Steel, 16; Carbon, 1.7; Brick dense, 1.3; Concrete (medium) 0.7; Epoxy, 0.35; Fiberglass, .04.

Story tip from EdLongRange. We welcome reader submissions.
Permalink Gear Review, Gunsmithing 15 Comments »