Origin of the .408 CheyTac®

The .408 CheyTac® Cartridge: Its Origin,
Firing Platforms and the Future©

The .408 CheyTac® cartridge and military firing platform (CheyTac® Model 200, Intervention) have received a great deal of attention as the star in the movie, SHOOTER, up and coming Batman Vs Superman and the following TV programs: “Law & Order, Criminal Intent (The Albatross)”, Discovery Channel, “Future Weapons” and the “Ted Nugent” hunting show.

Because the cartridge possesses extremely long-range sub MOA accuracy, many shooters are interested in its origin and the steps involved to bring it to its present state as well as to the cartridge’s future.  Such interest extends to early firing platforms up to the current military, law enforcement and civilian platforms.  A search of the Web under “.408 CheyTac®” reveals many sites with incomplete information and in some cases, information in error.  As a result, I have been asked by many to prepare a historical review on the .408 CheyTac® cartridge before the real history is lost to legend.  I will bring this review to the cartridge’s current status, particularly in reference to military adaptations and to the future where the .408 CheyTac® serves as a parental cartridge to other calibers, such as the .375 CheyTac®, which is beginning to make a name for itself as an extremely long-range sub MOA cartridge for civilian shooters.

I appreciate a historical review because some years back, I spent a fair amount of time tracking down the origin of the .338 Lapua Magnum (1, 2).  At the time, many thought Malcolm Cooper, an outstanding competition shooter and of Accuracy International fame designed the first cartridge.  In some sense that is true, but the .338 LM is based on the .338/.416 Rigby cartridge designed by James Bell and Boots Obermeyer.  This cartridge came about as a result of a US Navy contract for a new long-range sniper rifle (2).  Before his untimely death, Cooper agreed with me that the parental cartridge to the .338 LM was the .338/.416 Rigby cartridge with some important changes.

I am still in love with the .338 LM cartridge having three sniper rifles chambered for this cartridge; i.e., Sako TRG 42, AMP DSR No. 1, and a rifle of my design using a Sako TRG S action, Harris polymer stock, a Krieger barrel and Bruce McArthur’s brake; the rifle is known as Magenta Mist and in its day had quite a reputation.  Chambered for the Sierra 300gr SMK projectile, the Mist is capable of shooting 4-inch 5-shot groups at 1000 meters.


Some 18 to 19 years ago when I changed my primary interest from cancer research to a new challenge, I wrote a short story entitled, Some Live, Some Die based upon the interactions between a US military sniper and a thoracic surgeon during the Vietnam Conflict.  In preparing background material for the short story, it became clear to me that the .338 LM had distance limitations and the 12.7mm (.50 BMG) had accuracy limitations.  In addition, during this period, many were claiming the .338 LM was the intermediate between 7.62mm (.308 Win.) and the 12.7mm.  However for a true intermediate, the caliber would have to be 40 because the .338 is closer to a 30 caliber than to a 40 caliber.

With a 40 caliber in mind, I reviewed existing cartridge cases that might serve as a parental case rather than designing a case from scratch (3).  I was fortunate because the .505 Gibbs turned out to be perfect – well almost perfect.  George Gibbs of Bristol, England created the cartridge in 1911 with a low-pressure design, which meant the cartridge’s web as well as the wall close to the web had to be redesigned in order to arrive at a modern, accurate very long range 40 caliber sniper cartridge.

Modern wildcat designers start with a modern cartridge case, which they modify to accommodate a smaller or larger caliber projectile, or blow out the shoulders to increase the powder load; however, I was looking at a 1911 cartridge case design that had to be redesigned internally and then downsized to accommodate a smaller and hotter caliber.  Was this task worth it due to the fact that the .505 Gibbs is not a common big-game cartridge and finding modern cases would be extremely difficult, if not impossible?

Unable to purchase modern cases for a wildcat design, I would have to convince manufacturers who work in the hundred thousand cartridge case runs to make 100 to 1000 cases.  This would be almost impossible, as they could see no profit in working with a “nobody” with a wild idea.  I am convinced this is the reason why wildcat cartridges today are based solely on existing case designs rather than new designs and as a result, some wonderful design(s) may never be made; a potential loss to target shooters, to hunters and to the military.  Remembering the past, we created the ability to help some shooters with new innovative designs, Jamison International.


A. Cartridge

The .505 Gibbs cartridge was designed for a maximum chamber pressure of 45,065 psi (Piezo) with most commercial loads yielding chamber pressures in the mid-30,000’s psi accompanied with muzzle velocities in the low-2,000’s fps.  What brand of .505 Gibbs cartridge case was available to conduct initial studies?  Bruce Bertram of Bertram Bullet Ltd. (Australia) was selected, but Bruce was manufacturing his cartridge cases for chamber pressures associated with the original .505 Gibbs cartridge.  Would the Bertram cartridge case, in its original state be the best choice to launch a 40-caliber projectile to meet the desired projectile goal out to 2000 meters with a chamber pressure in the low 60,000s psi?

After some negotiations, I was successful in convincing Bruce to strengthen the web, but even with this modification I was apprehensive that the redesigned case would not perform well with an anticipated chamber pressure in the low 60’s psi.  My worry was the case wall that merged with the web.  It turned out that the Bertram cases worked, but could not be reloaded.

During this period, the first firing platform chambered for the 408 CheyTac® was constructed by Willi Wordman (retired machinist from General Dynamics and later, my partner in T.H.E.I.S).  Some cartridge developers approach such a task by putting together a “bare bones” rifle without any consideration to its overall appearance and details in the machining.  These platforms are usually referred to as “shop mules.”  A shop mule was constructed and called Prometheus by the Willi who constructed the rifle’s action.


Prometheus turned out not to be what we wanted.  We did use it for the first testing of the .408 CheyTac®, but shooting was restricted to 100 yards.  Another platform design was found, which I will address later in this article.

A die was made to neck Bertram cases down to .408.  Using the Sierra .338 LM 300gr MK projectile as a standard, ratios were used to up-size to .408 resulting in the first projectile design.  This was a solid.  I was convinced from the beginning that a solid projectile would be ideal for extreme long distances because the homogeneous copper alloy composition of the projectile would facilitate staying on the original trajectory path. During early projectile design, projectiles with driving bands were made and tested.


Maximum muzzle velocity was the goal and I felt the band would deliver such velocity.  The driving band was not my idea but a shooter in the Chicago area, whose name is lost in history, suggested this design.  The driving band was soon forgotten and we settled on a projectile without a band.

Dave Manson of Dave Manson Precision Reamers (Division of Loon Lake Precision, Inc., Grand Blanc, MI) was extremely helpful in mating the projectile to the cartridge case.  Willi and I worked closely with Dave to design the first chamber reamer and thus the first of many evolutionary designs for the .408 CheyTac® cartridge.

O. Kelly Tool in Lavonia, MI was identified to make the second solid projectile.  This was essentially my design without the driving band.  The first three-shot group at 100 yards showed promise.


Interesting enough, the first cartridge was not called the .408 CheyTac® but instead, the .400 Taylor Magnum™.


I thought the name would get lost in the thousands of wildcat cartridges and being a .408 – one full caliber larger than a .308 and with a name of a new company I was forming, it might have a better chance of military adoption.  Several “gun writers” at the time thought I was nuts because the military would not be adopting any new small arms cartridges.

With time, it became clear that if we wanted a successful .408 CheyTac® cartridge, we needed to find another cartridge case manufacturer.  The Bertram case would not stand up to reloading.  I approached Jim Bell and his son Jay (MAST Technology) about making a .505 Gibbs cartridge case.  Needless to say, Jim was not thrilled with the idea.  Jim was known for making a high quality .416 Rigby base case that could be used as a parental case for wildcatters.  My approach to him was that he could become even more famous making a .505 Gibbs case.  The logic behind this approach was that clearly the .505 Gibbs case could serve as a parental case for other wildcat cartridges.

I suspect one of the reasons Jim finally decided to help me was that he was shown the .408 CheyTac® cartridge made with the Bertram case and he remarked as he held it in his hand, “This is the cartridge Boots and I should have made rather than the .338/.416 Rigby.”

The task was given to Jay Bell and a year or two later, Jay was making .505 Gibbs cases with a strengthen web and strengthen wall continuous with the web.  I didn’t know at the time, but making the .505 Gibbs case is not an easy task.  Jay was making more rejects than final cases and unless something was done, MAST would lose money and I would be out in the cold.  Later I would find that making the .505 Gibbs case is very difficult unless one uses a cup made for the cartridge.  Some cups can be used to make different caliber cartridge cases, but it appeared the .505 Gibbs needed its own cup.  Later, when I was working with Marc Jamison of Jamison International, Marc determined that a specific cup had to be made for the .408 CheyTac® cartridge case.

Cartridge load development was accomplished with the assistance of Dr. Steve Faber (Fabrique Scientific, Batavia, IL).  During load development, a strain gauge was glued to the barrel over the chamber region.  This was connected to the Peak Strain Meter, developed by Dr. Steve Faber (4).  The Peak Strain Meter is a small plastic cased meter powered by a single 9V battery providing an LCD numerical readout of the strain reading.  The gauge is a thin plastic film with a resistive circuit pattern that measures to the nearest millionth of an inch, the elongation in the rifle’s chamber when the cartridge is fired.  The strain is proportional to the chamber pressures, which determine relative pressure or absolute pressure when calculated using a pressure vessel formula.

Initially, I faced a major problem testing new projectile designs and that was the lack of a long range such as 1000-yards or 1000-meters except once a year at Camp Grayling.  The Camp is located in central northern Michigan, is the largest military installation east of the Mississippi River, and the largest National Guard training site. Year-round training is conducted on 147,000 acres by the National Guard, as well as active and reserve components of the Army, Navy, Air Force, Marine Corps and Federal Law Enforcement.  I met with the Camp’s Commander as well as with his staff to see if I could obtain access to their 1000 meter ranges when not in use.  We discussed several sites on the Camp and finally the Colonel turned me over to a Major.  This was going to be tricky but at least they were talking to me, a university professor whose specialty was cell and cancer cell biology.  I’m sure the Major felt he had better things to do rather than accommodate me.  Keep in mind that all of these events were before 9/11.  Testing the new solid copper alloy projectiles at Camp Grayling was never conducted due to an announcement that David Brennan (editor, Precision Shooting magazine) sent to me.  Warren Jensen of Lost River Ballistics Technology (LRBT) had a new 30-caliber solid copper alloy projectile that was designed using PRODAS software.  He called this design Balance Flight and with time would be covered by a patent (6,629,669).  LRBT is no longer in existence and we own the license for the patent.

There is a saying in law that a patent is only as good as the money one wants to spend protecting it.  We discovered at the US Army Proving Grounds, Yuma, AZ that the Balance Flight design shows a unique Doppler pattern not seen with other projectiles, including cannon.  Evaluations of other projectile designs have not shown this pattern so it appears to be unique to Balance Flight.

It is clear that a projectile being able to retain stability throughout its flight will go farther and will be more accurate.  Warren identified conditions that could be translated into a projectile design, which would exhibit very long distance accuracy.  Working with PRODAS software, projectiles were designed in multiple calibers, where the linear drag on a projectile is matched to its rotational drag.  In other words, forward rate of deceleration and an axial rate of deceleration are balanced.  The gyroscopic stability remains constant resulting in the projectile remaining on its original trajectory path.  Non-balance flight occurs when a projectile’s spin is too great, thus leading to an “over spin” of the projectile.  Over spin leads to projectile destabilization — first expressed as projectile yaw, then to projectile tumbling, then to the projectile leaving its original trajectory path and finally the projectile falling to the ground.

An important component of Balance Flight is the design of the barrel lands and grooves. A ratio of a total surface of the projectile to a total surface area of the physical feature in the range of to 3.00:1 to 4.00:1 is critical.  As a result of projectile and barrel land / groove design, the drag coefficient is reduced to a range of 0.100 to 0.250.  In addition, the bearing surface of the projectile has a depth equal to 1% of the caliber of the projectile and a ratio of a total surface area of projectile to the total surface of the physical feature in the range of to 3.00:1 to 4.00:1.  The purpose is to impart an ideal axial surface friction upon launching, which during flight produces a trajectory characterized by a continuously decreasing rate of axial deceleration.

Dr. Faber and I made a trip to Arco, ID to meet Warren and see his shop.  The trip resulted in me asking Warren to make three PRODAS .408 designs for my review, which resulted in me selecting one.  This is the 419gr projectile used today.  Later, Warren went back to PRODAS and came up with a 305gr projectile, which we will be using in our new Natter Battlefield Domination Rifle (BDR) because of its extremely flat trajectory.

The next manufacturer of the .408 CheyTac® cartridge case was Dieter Horneber of Germany.  Dieter makes small batches of “out-of-date” cartridge cases for Norma Precision AB (Sweden) and took on the project with some glee.  The good news was the quality was outstanding; the bad news was that Dieter could only make 6,000 cases per year.

The next manufacturer was Marc Jamison of Jamison International.  Like most people Marc fell in love with the cartridge because of its balanced appearance.  At the time, he was in California getting ready to set up shop in Sturgis, SD.  Once settled in Sturgis, Marc started in earnest to make the case using 50-caliber cups.  Didn’t work.  Then cups from other calibers; didn’t work and so on.  It was clear that the caliber required an especially designed cup and Marc went to work designing it.  Would it be the correct design?  Only way to tell is to purchase newly designed cups from Olin, but the smallest order was 10 tons.  Olin had some mercy by selling 5 tons to me even though they would not guarantee the cups because their cup-making process requires 10 tons minimum.

Marc started making cartridge cases.  Some were good and some were bad.  A tremendous amount of pressure was on Marc to get these cases right because we were selling rifles and with each rifle went 4,000 cartridges.  At times, quality control was good and at other times, quality control lapsed.  It is about this time that one of the partners, Corey Kupersmith, purchased all of the equipment from Precision Made Cartridges (PMC) – 36 eighteen-wheelers filled with equipment and new cartridge case lines were set up in Sturgis.

Paul Jannuzzo, CheyTac®’s Chief Operating Officer and former COO of Glock Firearms, brought in some retired experts to set up the lines bringing the quality control to the highest level.  Marc who has made a lot of different caliber cases, including some of his own design, told me that the .408 CheyTac® was the most difficult.  Maybe any future competition will have the same experience.

B. Model 200 (Intervention), Model 300 (Shilo) & Model 310

I was in Northern San Diego County visiting my mother.  It is here that I met with Tom Miller, an agent for Alcohol, Tobacco and Firearms.  Tom is a big man, whose ATF responsibility was to break down doors on raids with an MP 5 in his hands.  His shooting career goes back to the time when he was a kid.   With a picture on their cover, Rifleman Magazine presented Tom to the world as a young competition shooter.  Tom had read several of my articles and was impressed with Magenta Mist and asked us to build one for him.  Tom was getting in to 50-caliber shooting and wanted me to meet with Bill Ritchie, owner of EDM Arms.  We took a drive to Riverside, and I met Bill and saw his Windrunner.  I fell in love with the design and felt that if this design could be downsized, chambered for the .408 and a few modifications made, it would make an ideal military very long-range sniper rifle.

After several discussions with Bill and mortgaging all of the funds in a new company that I had started; i.e., THEIS (Tactical High Impact Systems), we came to an agreement that Bill would make a prototype, which I still have.  This is about the time that I became acquainted with Dean Michaelis.  Dean is a retired Special Forces sniper instructor and author of the informative book usually referred to by it shorten title, Hard Target Interdiction (5).  My sense was that Dean was in love with Bill’s design as well and the two of us started a friendship that led into some business ventures.

We did not make any changes to the prototype design before it was made, but improvements were made after its completion.  The following are the changes that were made to our prototype design that later Bill incorporated into our rifles and I gave him permission to incorporate into his Windrunner.

  • Changed butt end of stock from cast steel to cast aluminum.
  • Changed trigger guard from steel casting to hollowed-out aluminum casting.
  • Cut down the thickness of the butt plate rod guides on the receiver.
  • Changed the cover plate on the butt plate rod-locking device (left side of receiver) to a lightweight Delron plate.
  • Changed the magazine “lock up” system for a lightweight design.
  • Extended the bi-pod rod forward to increase shooting stability.

Another change, which I don’t believe Bill has adopted on the Windrunner, is the following:

  • Removed the large iron ball from the bolt handle and exchanged for a light weight DELRON “cone type handle”

One of the problems with the EDM design is that we had to have the magazines made separately.  We found a company called Mag-Tech and the owner was more than happy to work with us.  For anyone who builds a repeater rifle, my suggestion is to build it around a completed magazine.  Getting a perfect, consistent designed magazine plagued us for some time.  That problem is now corrected.

Before Prometheus was completed, a rifle action manufactured by Tony Gilkes .50 BMG action came to my attention.  This impressive design, particularly its 45-degree angle on the locking lugs.


Several conversations with Tony convinced me, that his design would be ideal if made in titanium.  The design was purchased from Tony with a goal of down sizing it from a .50 to a .408 CheyTac® cartridge.  We had four made in titanium, but I was a bit unhappy that the action was not downsized more than it was.  It was basically a .50 action chambered for the .408 CheyTac® cartridge.  Two of the four were stocked in two different McMillan stocks.  Dean Michaelis did the initial testing in Arco and claimed that this was the most accurate rifle that he ever shot.


This was called the Model 300 Shilo.


At that time, we started a relationship with Barney Lawton (Lawton Machine, LLC), who was making barrels for us.  We were unhappy with the barrels that came with the Intervention.  Barney was interested in designing an action, which he did and Dean turned his attentions away from the Shilo to the action that Barney was making.  This action, smaller than the Model 300 handled the .408 nicely.  As a result only 4 Shilos were made.  We use the Lawton action for our law enforcement and civilian models for several years.

The first batch of Intervention was made and primarily sold to civilians.  Our goal was a military rifle but we learned several things about the RND design.  It was an accurate rifle design, but we felt it could do more with the .408.  As a result, rifles coming from RND had to be tweaked and later using a Barney Lawton barrel in order to display the accuracy required.  We replaced the brake with one made by Bruce McArthur (Flint & Frizzen, Clarkston, MI) – one of the best brakes I have encountered.  Another problem facing us was the RND parts were not interchangeable.  Clearly we had an accurate rifle but it would never pass military inspection or be capable of volume production.

It was about this time that some of the rifles were used for overseas operations.  Operations are still classified, so can’t say much about this other than the operators using the rifles came back with some useful suggestions to evolve the design.

The Intervention was becoming more and more popular but we were spending too much time tweaking it.  As a result, we changed manufactures and began work on introducing a next generation and lighter platform.  Is the design completed?  I doubt it as we are on a continuously improvement journey.  As more and more operators use it, they may have suggestions to improve the design.  We listen closely.

Intervention M200 has been successfully deployed in Afghanistan, Iraq and in places that we have no knowledge.  We guarantee 1.5-mile first shot hits in the hands of a qualified shooter.  In combat, US Marines have reported first shot hits of 1.3-mile in combat.  I suspect combat distances have improved since then.  One NATO military has reported that first shot hits at 1700 to 1900 meters drop so much kinetic energy causing targets to do backward flips.

C. Support

Intervention and the .408 CheyTac® cartridge seem to get all of the attention but experience shooters and operators know the core of the CheyTac® system is the Advance Ballistic Computer (ABC).  It turns out that a number of variables which affect accuracy are introduced after 1000 yards.  They include the Coriolis Effect (rotation of the earth under the projectile while in flight – 6-8 sec.), changes in barometric pressure, temperature of the cartridge, wind etc, etc.  Dean Michaelis, who had extensive experience with long distance shooting had developed a number of approaches to obtain accurate placement of projectiles.  Working with John Paver – one of the previous owners of CheyTac® and his son, Raoul, they designed software that allowed accurate placement of projectiles on the target over 2000 meters.  Later John and Raoul improved the software design and continue to mate it with new and better handheld computers.  In addition to having the .408, the ABC accommodates all military small arms calibers plus a large number on non-military calibers.  It turns out one cannot just come up with the best ballistic software in the world and then quit.  John and Raoul primed an industry, many providers are constantly updating the software, making it more and more user friendly.  This must be the reason US and a number of NATO militaries are using the ABC.

John’s expertise goes beyond the ABC.  As an experienced shooter with an in-depth knowledge of firearms, John turned some of his attention on new weapon designs going in and out of prototype development.

Another past owner and previous President of CheyTac® was Corey Kupersmith. His background is pharmacy tied to medical publishing along with real estate development.

With the acquisition of Jamison International as well as other important developments CheyTac® manufactured weapon, cartridges and accessories.

D. The Glue & Focus 

Paul Jannuzzo served as Chief Operating Officer and General Counsel.  Paul’s background included a county prosecutor, trial attorney, as well as Chief Operating Officer, General Counsel and Corporate Secretary for Glock Inc.  Before coming to CheyTac®, he served as a consultant for Kronstadt Advisory Services Corp.  In this position he focused on operational effectiveness, strategic sales, and growth planning and infrastructure design just to name a few activities.

Paul, John, Corey, and I all left CheyTac® and Mac McCutchen operated the company for about four years out of Nashville, Georgia. September 28, 2015 Dennis Omanoff, a highly successful executive with humble beginnings closed a re-formation of CheyTac® pulling in highly valuable patents, my previous company entities and along  with Mac McCutchen, the current CheyTac® majority owner, and Joe Warren, an investor and CFO, the new CheyTac® was born!

With CheyTac®, Dennis has been able to gather a number of isolated pieces and put them together into a highly focus team that represents CheyTac® today.  Serving as the spark plug for the future, which includes product diversification, product licensing, business alliances and channel partnerships.

D. The Headquarters & Training Facility 

CheyTac®’s headquarters and training facility was located in Arco, ID.  The facility was used to train US and NATO militaries in the use of the .408 CheyTac® firing platform along with the ABC.  Dave Durham led the facility and served as master armorer and instructor.

Today our HQ is located in Nashville, Georgia and we have key people deployed across several states.


No matter how good our products are if the military and law enforcement are unaware of their existence and their ability, we will soon be out of business.  Chris Kinney served as CheyTac®’s Director of Sniper Training (domestically and internationally) as well as Director of Military / Law Enforcement Sales.

For those of you who witnessed the Future Weapons segment on the .408 CheyTac® cartridge and Intervention, Chris was the individual guiding the use of the weapon to the Future Weapon’s host.


The .375 CheyTac® is derived from the .408 and what a wonderful cartridge it is.  Better?  Not better, but different.  There is evidence that a number of wildcats have developed from the .408 cartridge case, but the .375 is the first that we have released.  Several additional wildcats are in the wings waiting to be released at the appropriate time.

Who was the first to come up with the .375 concept?  Probably several people thought of it early in the life of the .408, but my search leads to Dave Durham as being the first.  We did not move forward as most of our attentions were focused on the .408 and thus Dave’s recommendation was not acted upon.  But the next critical step was Barney Lawton and Bruce Baer made a firing platform; i.e., Model and necked down the .408 to a .375 caliber.  As far as I can tell, they were the first to shoot the cartridge.  Later, Barney made Dave a .375 barrel for the Model 200 and Dave shot to determine ideal loads.  Still later, Dean Michaelis saw the Dave’s platform and became totally immersed in it.

There is some indication that others were making the .375 as we heard rumors of such wildcats.  My guess is that they do not all have the same specifications.  It is for this reason, we moved to standardized the caliber as the .375 CheyTac®.


Come Ups (MOAs) 1,2
Cartridge 2000 yards 2500 yards
.338 LM
250gr Senar @ 3150 fps
impact vel. 1050 fps
.375 CheyTac®
350gr CheyTac® @ 3200 fps
impact vel. 1580 fps
impact vel. 1355 fps
.408 CheyTac®
419gr CheyTac®
impact vel. 1261 fps
impact vel. 1070 fps
.50 BMG M-33 Ball
661gr @ 2910 fps
impact vel. 993 fps
.50 BMG M-211 (Raufoss)
665 gr @ 2910
impact vel. 996 fps
.50 SLAP
360gr @ 4000 fps

1 – Data corrected for sea level
2 – Comfirmed Advance Ballistic Computer (ABC) by CheyTac® Associates

NA = Not applicable

Come Ups = Scope elevations in order to reach 2000 or 2500 yards. The smaller the number the flatter is the trajectory.

In order to shoot very long distances, the rifle must be equipped with riflescopes that have the ability to elevate the reticle in units of MOAs.  These elevation units are called “come-ups”.  Scopes with high numbers have the ability to zero at very long distances.  The value of 140 MOAs found with the Leupold Mark 4 M1 16X is used for very long distance shooting.

On the other hand, cartridges that require lower number of come-ups in relation to other ammunition have flatter trajectory compared to other ammunition.  Thus evaluating come-ups from one type of cartridge to the next gives us a comparative evaluation on trajectory flatness.

The .338 LM elevation “come-ups” was greater than the .375 CheyTac® and the .408 CheyTac® but less than the .50 MBG M-33 Ball and M-211 at 2000 yards.  Thus .375 CheyTac® and .408 CheyTac® trajectories are flatter, but the .338 LM trajectory is flatter than the .50 MBG M-33 and M-211 at 2000 yards.  Note that .338 LM velocity is close to extinction.  The .338 LM did not reach 2500 yards.

The .375 CheyTac® showed the flattest trajectory with the greatest projectile velocities at 2000 and 2500 yards.  The .408 CheyTac® came in second.

The .50 BMG M-33 and M-211 trajectory are not very flat and the projectiles did not reach 2500 yards.  At 2000 yards, their velocities are close to extinction.  The .50 SLAP projectile did not reach 2000 or 2500 yards.

Another important consideration is the speed at which projectile enters the transonic zone.  As a rule of thumb, this is 1130 fps depending upon the projectile’s shape, BC etc.  Once into the subsonic zone, the projectile’s trajectory is unpredictable; however, “balance flight” design projectiles tend to stay on their original trajectory.  Hence, it is extremely important to know the target impact velocity as it relates to accuracy and thus their inclusion on the above table.  The .408 CheyTac® meet the velocity criteria at 2000 feet and is slightly short at 2500 feet.  However, note the superior performance of the .375 CheyTac®.

In closing, the use of “come-ups” is not the ideal approach to gather analytical data.  The proper approach is Doppler radar, which tracts the projectile’s external ballistic characteristic millimeter-by-millimeter down range.  Doppler radar will analyze the cartridges presented here in the near future.

SIGNIFICANCE: These data illustrate that .338 LM and .50 BMG M-33 and M-211 cartridges should not be used for extremely long distance shooting (beyond 2000 yards).  Other data, not presented here, demonstrate that these three cartridges are not effective for delivering adequate kinetic energy at very long distances.

We have a number of new designs in the Model 310 configuration.  This can best be seen in the rifles presented in this website.

We have two semi-automatic .408 CheyTac® rifles that are in the prototype testing stage.


The former is intended for law enforcement / civilian use while the latter is intended for military use.  For the military weapon, the 305gr projectile’s trajectory is so flat that the cartridge will dominate a 1000-meter battlefield.  Zero at the level of the kneecaps of a humanoid at 1000 meters, the rifle will hit targets from zero to 1000 meters without changing scope settings.

What does the future have in store for us? I can visualize a sniper cartridge that has a sub MOA at 4000 meters.  I can visualize several firing platforms for this cartridge – one might surprise you.

We are expanding into the field of lasers.  With our newly discovered technology, we believe we can harness the wind, design a new night vision with greater power and features over those used by the military today, design a technology that will identify snipers before they take their first shot and triggermen before they send a radio signal to a buried Improvised Explosive Devices and design a new range finder with greater distance and definition over what is currently in use today.  We plan to have these on the market within six months.

We are looking at a novel projectile design in 5.56mm and 7.62mm calibers that will deposit twice the kinetic energy into targets than existing projectiles currently used by the US military.  We have already developed a better armor piercing design than what is currently being used.  The .408 CheyCorey™ Armor Piercing (AP) outperform the 12.7mm AP (silver and black tips) using 1-inch rolled armor steel at 100 yards as a benchmark.  The 12.7mm AP fails to perforate while the .408 AP perforates with ease.  In addition, it maintains sub MOA out to 600 yards.

We believe the .408 CheyTac® cartridge should play a prominent role in hunting — especially big game hunting.  Hunting projectiles will be designed and loads are being developed for ultimate big game hunting.

CheyTac®’s primary goal is to create new products that create new battlefield tactics for the US military as well as for our allies.  We have been fortunate to bring in some of the top people in management, marketing, law enforcement and on the ground military experience in recent and ongoing conflicts.  I am honored to play a small part of this.

John D. Taylor, Ph.D.
Colorado Springs, Colorado


  1. Taylor, J. D. 1999. The .338 Lapua Magnum Cartridge: Origin, Development and Future. Part I. Tactical Shooter, Vol. 1, No. 12, pp. 52-66.
  2. Taylor, J. D. 1999. The .338 Lapua Magnum Cartridge: Origin, Development and Future. Part II: The Men Behind the Cartridge. Tactical Shooter, Vol. 2, No. 1, pp. 22-25.
  3. Taylor, J. D. 1997. Parental Cartridge Cases: The Future. Shooter’s News, June, pp. 15-27.
  4. Faber, S. Internal Ballistics. http://www.mindspring.com/~sfaber1/
  5. Michaelis, D. 2000. The Complete .50-Caliber Sniper Course. Hard-Target Interdiction. Paladin Press, Boulder, CO.