The story of .338 Lapua Magnum, pt 1

In this two-part feature, we share the background behind the legendary .338 Lapua Magnum and how it came to be a cartridge from Finland, even though the idea was born on another continent.

The .338 Lapua Magnum caliber originates back almost forty years to 1982, when the .338/416 cartridge was developed for the United States military purposes. Officially, the project was to develop a target rifle and cartridge for 1000 yards, but in reality the purpose was more likely to develop a 1500 meter sniper rifle.

The .300 Winchester Magnum and other commercial cartridges did not meet penetration requirements, so the search for a heavier caliber with better ballistics was on. The result was a new wildcat cartridge that was originally formed from a necked down .378 Weatherby Magnum case, and finally from the .416 Rigby case. The new cartridge was known as the .338/416 or 8.58×71.

Lapua finished development of the first bullets and cases for the .338/416 cartridge in 1985. Its first .338 caliber projectile was the B408, which in 1985 looked more like a D46 bullet on steroids than the Lock Base type currently produced.

In 1986, the .338/416 cartridge with a Lapua bullet and case won the 1,000 yard navy rifle competition in Quantico, Virginia. In spite of that, the U.S. military selection criteria went in a different direction. At that point, Lapua was left more or less alone with the new caliber cartridge, still management decided to continue product development. This resulted in specifying the measurements, and the cartridge was named the .338 Lapua Magnum. The .338 Lapua Magnum was slightly different than the original .338/416 case. Case and chamber dimensions were modified, along with the interior structure of the case to withstand higher chamber pressures than the .338/416 design. The .338 Lapua Magnum had arrived.

Continued in part 2!

Lapua Ballistics Tips: Stability Estimation

(Click here for the Lapua Ballistics Tips page and previous tips)

Some basics about bullet accuracy and stability estimation

Stability is an essential part of bullet accuracy. Stability is affected by several factors, the most important factors being barrel twist rate and the length of the projectile. To a lesser degree it is also affected by the bullet shape, velocity and environmental conditions. You can estimate bullet stability during the flight path with the stability estimator function in Lapua Ballistics. In this article, we will explain bullet stability to a high detail and how to use Lapua Ballistics as a tool to understand it.

What is barrel twist rate?

Twist rate is defined as the length of one full turn of the bullet (360 degrees) in inches or millimeters in the barrel. E.g. 1:10” means that the bullet makes one full turn over the distance of 10 inches. You can measure the twist rate of your rifle barrel by marking e.g. a cleaning rod with a flag made of adhesive tape, and measuring the distance where the flag rotates 360 degrees. Make sure that the cleaning rod follows exactly the lands in the barrel.

What happens if the bullet is too long compared to the twist rate?

If the bullet is too long compared to the twist rate, it will be unstable and may start to wobble or even turn completely crosswise. For the shooter, this translates as poor accuracy and oval or ”keyhole” shaped holes in the paper target. An overstabilized projectile does not follow exactly the trajectory of the curved flight path but flies slightly nose up. Technically speaking, the axis of the bullet does not follow the tangent of the trajectory. This increases the air drag and shortens the flight range. An unnecessary high rotation speed also intensifies the adverse effect of smaller shape and symmetry defects of the projectile.

Lapua Ballistics Bullet stabilization explained

How to increase bullet stability

The stability of a bullet can be increased by the following factors (roughly in the order of importance):

  1. Tighter (shorter) twist rate of the barrel
  2. Shorter bullet
  3. High altitude (lower air density)
  4. High temperature (lower air density)
  5. Low air pressure (lower air density)
  6. High humidity (lower air density. Yes, water vapor is less dense than air!)

Lower air density means less aerodynamic forces affecting the bullet so it remains stable easier.

Stability estimation – the theory

Traditionally, bullet stability is estimated by using quite simple equations like the Miller and Greenhill equations. Lapua Ballistics estimates the bullet stability by using both dynamic stability ’Sd’ and gyroscopic stability ’Sg’ during the full bullet trajectory. The value of the stability calculator is more in comparing different combinations with each other (twist rate, bullet to be used, muzzle velocity, environmental conditions, etc.) than trying to say simply if a bullet is stable or unstable.

Gyroscopic stability Sg means the ability of a rotating object to resist the change of its rotating axis. Sg is quite easy to calculate and its value at the muzzle has to be absolutely over 1.0 for a bullet to be stable. In practice some safety margin is needed there so the recommended minimum value is 1.4. Values clearly over 2.0 are unnecessary high because an overstabilized bullet has higher air drag due to the ”nose up” flight position and is more critical to small imperfections in the bullet shape and symmetry. Gyroscopic stability increases with flight time/distance because the rotational speed of the bullet does not decrease as fast as the forward velocity.

Dynamic stability Sd means the ability of the bullet to decrease a wobbling motion caused by an internal or external effect. In a dynamically stable bullet, the wobbling decreases with the time/distance and in a dynamically unstable bullet the wobbling increases with the time. Sd is much more difficult to evaluate than Sg and it needs 6 DOF calculations. Lapua Ballistics is one of the very few ballistics software solutions that is capable of utilizing this and possibly the only one completely free of charge. Most software are capable of estimating stability only by Sg which is usually reasonable good enough for short distances but not to long distances and to the transonic region – where Sd is the main factor for stability. The vertical axis of the stability curve expresses Sg and the horizontal axis Sd. The favorable stability region is expressed as light blue but high quality bullets often retain the stability also in the dark blue region.

Dynamic stability is affected by e.g. the bullet length and shape and the positions and distance between the center of mass (cm) and the center of pressure (cp). The distance between cm and cp is very important because it defines the aerodynamic moment vector that tries to turn the bullet crosswise. Air density is also important, the stability is better in a higher altitude and warm weather. The grooves (made by the lands in the barrel) on the bullet surface slightly affect the dynamic stability and decelerate the rotating speed faster compared to a smooth surface. Dynamic stability is usually the problem only at long distances and in the transonic region.

Stability is not an ON/OFF phenomenon, so Sg and Sd basically describe the tendency or risk for unstability. For that reason the graph in Lapua Ballistics is not black and white but light/dark blue. The bullet can fly – and often does – fly stable and accurate also far inside the dark blue region. As a rule of thumb, we can say that at the later (number of 100 m/yds markers) and in the more upper direction the line exits the light blue region, the better the bullet can resist external forces trying to make the bullet wobble, meaning that the stability and accuracy potential is better.

How to read the stability calculator in Lapua Ballistics

Simple guide for ensuring bullet stability

  1. The target for the gyroscopic stability value Sg at the muzzle is between 1.4 and 1.8. Never go below 1.2 and avoid values clearly over 2.0. This is a good guide for both short range and long range bullets. For most shooters this is enough and in that case, you don’t have to worry about the dynamic stability Sd.
  2. When you shoot long (over 600 m/yds) and extremely long (over 1 km/mi) ranges, you also need to pay attention to the dynamic stability. The stability curve should turn as late as possible (no. of distance markers) and only a little to the left. If the curve turns 90 degrees to the left it means a higher risk of unstability than if the curve turns only 45 degrees to the left. The stability curve of high BC long range bullets always turn clearly to the left.
  3. Long and sharp-nosed VLD bullets (Very Low Drag) may be problematic in the transonic region. Shorter projectiles tackle this problem easier but on the other hand they reach the transonic region earlier because of a lower BC. Transonic region stability can be improved by a tighter twist rate but this may have other undesired effects to the accuracy in general.

Example of bullet stability estimation in Lapua Ballistics:

Lapua Ballistics Stability Estimation 1

  • Gyroscopic stability Sg is expressed on the y-axis (0 – 5).
  • Dynamic stability Sd is expressed on the x-axis (-1 – +3).
  • Maximum values are expressed also as numerical values in the top left corner (here Sd = 0,2 and Sg = 2,6).
  • On the line, there are markers at each 100 m/yds starting from 0 m/yds but the line is actually calculated and shown in 10 m/yds intervals.
  • The safe stability region is expressed as a light blue area. In the dark blue region the risk for unstability is increased but it doesn’t mean that the bullet is unstable. Only the bullet ability to correct external disturbances (e.g. flurry or transonic area disruption) is reduced.
  • Gyroscopic stability at the muzzle (0 m/yds, first marker) should be at least over 1.0 (red line) and preferable over 1.4 (yellow line).
  • Gyroscopic stability increases with the distance (here 1.7 -> 2.6) because the bullet retains its rotational speed better than forward velocity.
  • Dynamic stability starts to weaken after 200 m/yds but in this case it is not dramatic and the bullet remains in the safe region up to 600 m/yds.

Effect of twist rate in .308 Win, example:

Lapua Ballistics Stability Estimation 308 Win

In this graph you can see the effect of the twist rate to gyroscopic and dynamic stability in a .308 Win. rifle with the 10,85 g / 167 gr GB422 Scenar bullet. This OTM bullet is mainly designed for short and medium ranges – up to about 600 m/yds.

  • The 1:14” twist rate (red curve) is too slow (i.e. long) for this combination. Gyroscopic stability at the muzzle is too low (first red dot) ca. 1.0. There is a high risk for the bullet to be unstable already at the muzzle.
  • The 1:12” twist rate (blue curve) is appropriate for this combination. Gyroscopic stability at the muzzle (first blue dot) is good, ca 1.4. The bullet travels the first 500 m/yds in a safe region and does not turn strongly left even after 500 m/yds. The bullet has good presumption to fly stable and accurate to long ranges.
  • The 1:10” twist rate (gray curve) is slightly too fast for this combination. Gyroscopic stability at the muzzle (beginning of gray curve) is slightly too high, ca. 2.0, but the bullet likely works fine and shoots accurate. But the bullet is spinning unnecessary fast and may be susceptible to adverse effects of small imperfections in shape or symmetry. A good combination, but maybe not the optimal one.
  • The exact Sg and Sd values can be seen in the trajectory table if Sg and Sd are selected as columns to be visible.
  • Please note that the software may calculate the stability values for longer distances than the shooting distance so the last marker may not be the actual shooting distance.
  • This feature is available only for Lapua bullets and cartridges because the details of bullet structures (e.g. moments of inertia, center of gravity, etc.) are not available for other bullets.

Effect of twist rate in .338 Lapua Magnum, example:


In this graph you can see the effect of twist rate to gyroscopic and dynamic stability in a .338 Lapua Magnum rifle with the 19,44 g / 300 gr GB528 Scenar OTM bullet.

  • The 1:12” twist rate (red curve) is too slow (long) for this combination. Gyroscopic stability at the muzzle is too low (first red dot), ca. 1.0. There is a high risk for the bullet to be unstable already at the muzzle. This combination is known to be in the limit of appropriate function – sometimes it works, but usually not.
  • The 1:10” twist rate (blue curve) is appropriate for this combination. Gyroscopic stability at the muzzle (first blue dot) is good, ca. 1.5. The bullet travels the first 800 m/yds in a safe region. Even when it exits the safe region at 800 m/yds, this bullet is well known for extremely good accuracy up to 1 500 m/yds and over. It is typical for all long high B.C. bullets that the Sd turns strongly to the left and exits the safe region.

How bullet length affects the stability

Lapua Ballistics Stability Estimation Lapua-Ballistics-Stability-Estimation

In this graph you can see the effect of bullet length to gyroscopic and dynamic stability in a .338 Lapua Magnum rifle with a 1:10” twist rate.

  • The shorter 250 gr GB488 Scenar (red graph) retains its stability better than longer 300 gr GB528 Scenar (blue graph), but reaches the transonic region a little earlier than the ballistically better 300 gr bullet. You can compare differences in bullet velocity and energy in their respective graphs and trajectory table.
  • If you can see a clear wave pattern in the trajectory curves, it is also an indication of potential instability. The most likely reason for this is a too slow (long) twist rate that doesn’t stabilise the bullet but allows for it to wobble from side to side or even turn crosswise. In this case, shoot paper targets to check that the holes are round and the accuracy is good enough for your purpose.

Extreme examples


In this graph you can see two .222 Rem. caliber bullets, both shot with a 1:14” twist rate rifle.

  • The .222 Rem is designed for short 55 gr FMJ-bullets (red curve). Even if the gyroscopic stability is dangerously low in the beginning (ca. 1.0), it increases rapidly and this short flat base bullet is not susceptible to wobbling. This combination is in practise a well-proven small game cartridge.
  • The 69 gr Scenar bullet (blue curve) is much too long for this twist rate. Gyroscopic stability starts from a very low value and also the dynamic stability starts to weaken significantly immediately. This bullet will likely not be stabilized at all and the accuracy potential is very low and likely the holes in a paper target are oval – even at 100 m/yds.

Temporary loss of stability


In this graph you can see a temporary loss of stability at a distance of 650 – 850 m/yds with a 6 mm 90 gr GB543 Scenar bullet. In this case the projectile reaches the transonic area at the distance of 700 m. Stability will revert soon after that and the bullet likely continues a stable flight without a loss of accuracy. This is also helped by the high gyroscopic stability value of over 3.5.


Lapua Ballistics 6 DOF is the only free of charge consumer software capable for these kind of studies. For those interested to understand the theory behind bullet stability even further, we recommend the following reading:

  • McCoy, R. Modern Exterior Ballistics, the Launch and Flight Dynamics of Symmetric Projectiles. Schiffer Publishing, 1999
  • Bryan Litz, Applied Ballistics For Long Range Shooting 3rd Edition
  • Sailaranta, T. Studies on Unmanned Atmospheric Flight. Doctoral Thesis. Aalto-University, Helsinki, Finland.

Our next tip will feature the use of spin drift adjustment. Stay tuned!

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New 300 Winchester Magnum factory-loaded cartridges by Lapua

New .300 Winchester Magnum cartridges for hunters and target shooters

For 2021, Lapua offers three new cartridges for .300 Winchester Magnum. The .300 Win Mag. is known for its extreme versatility and as such it’s a great cartridge option for hunters, target shooters, military and law enforcement departments alike. Lapua is happy to offer two new options for hunters and one for target shooters.

Hunting cartridges with significant stopping power

As the .300 Win Mag. is known for its accuracy, hunters have found the cartridge to be an effective all-around choice for various types of game and hunting conditions. Most firearms manufacturers chamber for this caliber and there are numerous rifle options to choose from. With the new .300 Win Mag. Lapua case we now also offer two new factory-loaded hunting cartridges:

  • .300 Win Mag. loaded with the 11,0 gram / 170 grain Naturalis bullet and
  • .300 Win Mag. loaded with the 12,0 gram / 185 grain SP MEGA bullet.

Both cartridges offer something for every hunter. A fan favorite for many years, the traditional MEGA is a lead core, mechanically bonded, soft point hunting projectile. The third generation Lapua Naturalis bullet with its special valve design offers a completely lead-free option with that perfect mushrooming effect. With muzzle velocities that enable extremely straight flight trajectories, these rounds are an obvious choice for long range hunting or for situations that demand significant stopping power.

Long range target accuracy with Lapua Scenar

For the demanding target shooters, long range enthusiasts and tactical units, Lapua offers the perfect cartridge option: the  .300 Win Mag. with the 12,0 g / 185 gr OTM Scenar bullet.
This round offers accuracy and power well beyond 1,000 meters/yards with the Scenar projectile staying supersonic. The unique design of the 185 grain Scenar (GB432) together with the short case neck and relatively short C.I.P cartridge specs create an undeniably powerful combination for long range target shooting. With a high quality powder and a muzzle velocity of 930 m/s or 3051 fps, this cartridge is destined to become the number one choice for any long range shooters demanding peak accuracy.

All three Lapua cartridges will be hitting the markets in the spring of 2021.

Go to the .300 Win Mag cartridge page for trajectory information here

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Lapua Ballistics tips: How to export trajectory tables to excel

Lapua Ballistics tips: How to export trajectory tables to excel

(For the previous Lapua Ballistics tips, click here for the Lapua Ballistics Tips page)

A trajectory table in printed form can come in handy on many occasions, eg. when hunting or if you want to compare trajectory data on your computer. With Lapua Ballistics, you can export trajectory tables in a printable format. In this tip, we will tell you how to generate a table and export it to Excel.

A few tips for exporting a trajectory table to Excel:

  • Consider the distances for which you want to create a trajectory table. We recommend creating a table including only the necessary data.
  • Select the cartridge profile you are using.
  • Update the weather conditions to match the conditions for which you want to generate the table.
  • The trajectory table exported to Excel contains all the calculations made by Lapua Ballistics within the given distances. Note that your Excel views may look slightly different depending on version and operating system.
  • The exported Excel file contains a considerable amount of calculated data. The visuality of the table and how to display the information is up to the user.
  • NOTE! To be able to export the .csv file to your email, you need to have an email address registered to your phone’s own standard email app.

How to export trajectory tables to excel in Lapua Ballistics, step-by-step instruction

Step 1: Choosing the data you want to export

  • First, pick the weapon/cartridge combo you want to use.  In this example, we’re exporting a trajectory table for the profile FMJ 308 Win.
  • Next, since you’re going to be taking into account the expected weather conditions, go to the Calculator view and tap “Get current weather”
  • You know that the shortest possible shooting distance is 50 meters and the longest is 350 meters, and you want to generate a trajectory table in 25 meter increments. Swipe to the second to last calculator view “Trajectory table” and add the said distances. Tap “Calculate”.
Lapua Ballistics tips export to excel pic 1

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Lapua Ballistics tips export to excel pic 3

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Step 2: Share the trajectory table to your registered email

  • The flight path table calculated on the basis of the previously provided data looks like the enclosed image.
  • To export the trajectory table to Excel you need to share it to your own e-mail. First tap the “Share” symbol at the top and then tap ‘Email’.
  • The Ballistics app should now open the phone’s email app with the table enclosed as a .csv file. Next, send the email to the preferred address (e.g. to yourself).
  • NOTE! To be able to export the .csv file to your email, you need to have your phone’s own standard email app in use.
Lapua Ballistics tips export data to excel pic 4

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Step 3: Export the trajectory table from your email to your computer and open in Excel

Next, save the LapuaBallistics.csv file from your email to your own computer to a folder of your choice.

Lapua Ballistics tips export data to excel pic 5

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After that, open an empty workbook in Excel, and in the toolbar go to Data (→ Get External Data) → From Text. Choose the LapuaBallistics.csv file from the location you saved it to on your computer. Excel now opens the Text Import Wizard. Click Next, which takes you to Step 2 of 3. Choose ’Comma’ as your delimiter → click Next → Finish.

Lapua Ballistics tips export data to excel pic 6

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After this, your Lapua Ballistics calculation with the given distances will open in Excel. The trajectory table is at the top of the table, other properties can be seen at the bottom. You can pick the information you want and display it in the way you prefer.

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…And you’re done!

Our next tip will feature the use of stability estimation. Stay tuned!

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Happy Holidays!

We wish you Happy Holidays and a Fantastic New Year 2021!

Lapua Ballistics tips: How to compare data in Lapua Ballistics

Lapua Ballistics tips: How to compare data in Lapua Ballistics

(For the previous Lapua Ballistics tips go to the Lapua Ballistics Tips page)

Lapua Ballistics offers you the opportunity to compare data for three different cartridges or bullets in the ballistic calculator.

You can use comparison data for your cartridges or bullets, for example to compare trajectories or impact velocity and / or impact energy in different hunting situations. You can also use the cartridge/projectile comparison to determine the best Point-blank Range (PBR) and to estimate stability. In addition, you can share the picture and information via email or other possible communication applications on your phone.

You can easily compare data in the Ballistics app for the following ballistics calculation features:

– Elevation

– Windage

– Velocity

– Energy

– Point-blank Range

– Trajectory

– Velocity / distance

– Energy / distance

– Stability estimation

How to compare data in Lapua Ballistics, step-by-step instruction

All these features are accessible in the lower views of the Calculator mode in the Ballistics app. In the comparison created, you can clearly see the differences between the 3 bullets / cartridges you have chosen in the same graphic.

    1. First, select the first Lapua cartridge from the Rifle / Cartridge Data menu, and check that the basic settings are correct. For example, you can set the desired muzzle velocity for the cartridge / bullet.
    2. Next, go to the Calculation mode, and swipe to the third lower view and tap to expand.
    3. Select as comparison item(s) either a custom cartridge you’ve created, or a factory-loaded Lapua cartridge from the drop-down menu. You can compare up to three items.
    4. Expand the lower view of the Calculator screen and swipe right to quickly and easily view the comparison data separated by different colors (here in red and blue).
Lapua Ballistics Cartridge settings view

Step 1. Go to cartridge settings and set eg. muzzle velocity (Sight-In V0 value) and other basic values for your cartridge/bullet of choice. (Tap image to expand.)

Lapua Ballistics expand lower view to compare cartridges

Steps 2 and 3. Open the Calculator and swipe to the third lower view and tap to expand. Choose the cartridges / bullets you want to compare. (Tap image to expand.)

Lapua Ballistics view lower views to compare data.

Step 4. Swipe right in the expanded view to quickly and easily view the comparison data separated by different colors. (Tap image to expand.)

You can also pick just one cartridge / bullet and compare different muzzle velocities, weather conditions and twist rates for that cartridge by copying it in the Manage Rifle/ Cartridge Data menu and changing the desired settings for the copied items.Next time, we’ll look at how to export trajectory tables to excel!

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New Open Tip bullets and factory-loaded cartridges by Lapua

New Open Tip bullets and factory-loaded cartridges by Lapua

For 2021, Lapua offers new Open Tip (OT) bullets and factory-loaded cartridges for target and hunting practice: Introducing the 8 mm OT bullet and 8×57 IS OT cartridge, and the 9.3mm OT bullet and 9.3×62 OT cartridge.

The 8×57 IS has earned a strong hunting reputation in recent years, but is now taking a step in the target shooting direction. Lapua Sales Manager, Erkki Seikkula, explains the thought process behind our new 8mm 7,8 g/ 120 grain OT bullet:

“We designed an easy and softly firing bullet that meets Lapua’s strict accuracy requirements. The precision of this bullet offers shooters the opportunity to practice with the same rifle that they hunt with. For avid hunters that enjoy target competitions, the performance of this projectile can really make a difference.”

A notable advantage of the bullet and the factory-loaded cartridge is that the bullet’s point of impact coincides with the Lapua Naturalis, making both products ideal for hunting practice.

The 9.3×62 has traditionally been used only with big game hunting in mind. Requirements have changed with time and today this rifle cartridge needs a bullet that offers a more diverse use of the caliber amongst hunters. Lapua has answered this demand and developed the world’s most accurate Open Tip bullet for this caliber, which extends its use to a diverse set of options from practice shooting to small predator hunting.

“The 9.3mm 12.0 g / 185 grain Open Tip bullet is available as a reloading bullet for home loaders, yet we also offer it as a factory-loaded cartridge for anyone for whom accuracy and performance matter when choosing a cartridge. Also here, the impact point of resembles that of the Naturalis bullet, making this the ultimate round for hunters training for big game hunts”, Seikkula says.

As with all Lapua products, ballistic data and trajectory information will be published on our website, with load data available by Vihtavuori Powders.

The new bullets and cartridges will be available in the beginning of 2021.

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New Lapua Brass Cartridge Cases for 2021


Lapua, world-renowned for producing the finest cartridge cases and ammunition products, is happy to announce the addition of 6.5 PRC, .284 Winchester, .300 Winchester Magnum, and .300 PRC cartridge cases to our 2021 product offering. Our new Lapua brass offerings for 2021 display our continued commitment to the precision shooting disciplines which are popular on a global scale.

New Lapua brass cartridge cases

The new Lapua 6.5 and .300 PRC cartridge cases provide competitive shooters, hunters and accuracy enthusiasts a premium selection for precision hand loads, an option that’s been missing from the market since the PRC’s inception.

The 6.5 PRC case

Although the 6.5 Precision Rifle Cartridge (or PRC for short) was originally designed for long range hunting, the 6.5 PRC is still an excellent cartridge for both long range sport shooting and hunting. Its increased case capacity enables velocities up to 80 m/s (262 fps) faster than the 6.5 Creedmoor or 6,5×55 SE. By design, the cartridge features a longer throat enabling the use of today’s popular, high ballistic coefficient (BC) projectiles for long-range competitions. The 6.5 PRC case is a good match with relatively slow burning powder types. It is a great choice for heavy bullets, exceeding even 9,7 g / 150 grains with excellent retained energy and terminal performance for mid-sized and large game.

The .300 PRC case

The .300 PRC was designed for extreme long range shooting with heavy bullets featuring high ballistic coefficients. Its superior ballistics and beltless case configuration represent modern
case design that supports the use of modern long and high BC bullets. With its ability to load heavier bullets, the performance of the .300 PRC exceeds the .300 Winchester Magnum and
many other .30 Magnums on the market. The .300 PRC is also an superb choice in open and large hunting fields for long distance hunting of mid-to-large sized game with bullet
weights exceeding 15,8 g / 245 grains.

The .284 Winchester case

The .284 Winchester cartridge has experienced a recent resurgence in F-Class competition, where shooters compete to distances out to 1,000 m/yd. Members of the US Rifle Team, which Lapua sponsors, will enjoy having cases readily available in this classic cartridge. The .284 Winchester’s rebated rim design enables a larger powder column, yet easily functions through medium length actions making it desirable for custom rifles. Its accuracy potential and high muzzle velocity is also recognized in hunting fields where this cartridge performs nicely on a very wide scale.

The .300 Winchester Magnum case

The .300 Winchester Magnum has been a staple within the firearms industry, widely used by hunters, target shooters, military and law enforcement agencies around the globe since its development in the early 60’s. It is still used for competitive target shooting, hunting, and Mil/LE platforms to-date. It delivers excellent long range performance with a wide range of bullet weights from 165 to 200 grains and more. The .300 Winchester Magnum has a great reputation as a .30 caliber magnum hunting cartridge in Europe and North America. Lapua’s .300 Win. Mag case will be a great addition to our line, especially with the huge bullet selection available for sport shooting and hunting for this caliber and all major rifle manufacturers chamber their rifles for it.

All new Lapua cases will be available for home loaders in spring of 2021.

Lapua Ballistics tips: The benefits of 6DOF

Lapua Ballistics tips: The benefits of 6DOF

(For the previous Lapua Ballistics tips go to the Lapua Ballistics page)

As most Lapua Ballistics users already know, Lapua Ballistics applies the 6DOF calculation to model flight paths for Lapua projectiles. 6DOF is also the calculation model used by Lapua Product Development. So what are the advantages of 6DOF, and what does it mean for a shooter requiring accuracy?

First, let’s take a look at some other means of modelling flight paths:

The 3DOF point-mass solution

The 3DOF calculation model considers only the drag coefficient, i.e. the Cd factor. Using 3DOF doesn’t require a large computing capacity. As the name implies, there are three degrees of freedom, i.e. translational components tracked in the equation: moving forward/backward; moving left/right; and moving up/down. 3DOF calculation doesn’t take any stance on the attitude (the orientation of the projectile relative to the direction of motion) or stability of the bullet, and has a very straight-forward and simple approach to crosswind. This means that the 3DOF model calculates the position of the bullet as a function of time reasonably correctly as long as the flight is stable. In windy or changing conditions, however, this model is not the most reliable.

The modified point-mass solution

The modified point-mass calculation (sometimes referred to as 4DOF) is more advanced than the 3D model, as the calculation includes three translational degrees of freedom and one rotational degree of freedom (spinning). The aerodynamic model includes also e.g. the contribution of lift force. These are some of the same forces that the 6DOF model calculates, however the point-mass model applies a simplified calculation which does not take into account the actual attitude of the bullet, but merely includes an algebraic approximation for the attitude (pitch/yaw angles) of the projectile. Due to some simplifications involved the model is not able to give information concerning the flight stability.

Why 6DOF?

The above mentioned calculation solutions are obviously usable for trajectory calculation. So the question is, what does the Lapua Ballistics 6DOF solution offer?

The easy answer is: the most accurate results. As with the modified point-mass model, the 6DOF calculation includes three translational degrees of freedom and three rotational degrees of freedom which give the position and attitude as a function of time. Simplified, 6DOF tracks both the pitch, yaw and roll as well as the up/down, left/right and forwards/backwards movement of the bullet.
The big difference to the other calculation models is that the 6DOF models the actual trajectory path of the projectile at all times during flight, instead of just calculating points on the trajectory curve. The stability properties of the bullet are obtained during the trajectory integration since all the rotational degrees of freedom are present in simulations. Also, the stability analysis of the Lapua ballistics app is more advanced than most other calculators, as it considers both dynamic (Sd) and gyroscopic (Sg) stability factors, not only the latter as many other ballistic calculators do. The Sd is especially important in long range shooting for analyzing the transonic stability of the bullet.

But how can the Lapua Ballistics app utilize 6DOF? It is after all a very complicated mass of data, something a mobile phone would not be able to calculate.

The explanation lies in the background information of the app data. Every 6DOF-calculation is based on an aerodynamic values table that is calculated for every Lapua bullet. The table includes several aerodynamic coefficients and bullet specifics: Drag coefficient derived from Doppler radar data, Normal force coefficient slope, pitching moment coefficient slope, roll damping moment coefficient, two stability derivate, Magnus force coefficient slope and Magnus force moment. All those coefficients must be functions of the Mach number.

These calculated values are taken into account for every Lapua bullet in the Lapua Ballistics app. This is also why we can’t provide the same level of accuracy for other bullets; utilizing 6DOF requires this background data.

Accuracy comes down to not only data, but to weather, equipment, mental preparedness and so on.  The Lapua Ballistics app gives you the best data to take that perfect shot. The rest is up to you.