Lapua Ballistics Tip: How to create a scope reticle

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

How to create a scope reticle for your rifle in Lapua Ballistics

Did you know that you can create an image of your scope reticle in our ballistics calculator? You can set up your actual scope reticle dimensions in the calculator view to give you an easy visual guidance in the app. Creating the crosshair is an easy process, you just have to calculate the number of lines in your reticle and know the distance between the lines.

How to create your scope reticle in Lapua Ballistics

  1. Go to ”Manage Rifle cartridge data” and choose the desired rifle-ammunition-scope system by tapping the pen symbol
  2. Go to the Reticle menu and scroll to ”Create”
  3. Name your reticle
  4. Add the number of main lines for the three directions (above and below center; left and right)
  5. Choose the correction unit (mrad – MOA – cm/100m – in/100yd)
  6. Give the difference between main lines in the unit you selected
  7. If you have secondary lines between main lines, tap Secondary lines ‘On’. Your secondary lines will then be visible halfway between main lines.
  8. Remember to save the changes you’ve made. Done! Now your reticle is the one displayed in the calculator view.
Create your reticle in Lapua Ballistics app
Create your reticle in Lapua Ballistics app
Create your reticle in Lapua Ballistics app

If the distance between the lines in your actual scope is not a constant, then you won’t be able to generate a correct looking reticle view, but all the ballistic calculations will naturally be correct nevertheless.

You should note that the distance (in mrad, MOA etc.) between the lines may or may not be a constant with different magnification settings, depending the type of your scope.

What is the difference between a SFP reticle and a FFP reticle?

A riflescope’s reticle is placed on either the first focal plane (FFP) or the second focal plane (SFP). The main difference between them is that an SFP reticle will appear to be the same size regardless of magnification. With an FFP reticle, the size of the reticle will appear to change as the scope’s magnification is changed.

Most hunters and shooters are familiar with SFP, as it has been the most commonly used in basic scopes. The FFP reticle has become popular especially with long-range shooters.

With an SFP reticle, the spacing for holdover in the reticle is only correct at one magnification, usually the highest setting. One advantage with this is that you get a strong and easy-to-see reticle even at the lowest magnification.

An FFP reticle appears to grow larger or smaller as the scope’s magnification is increased or decreased, respectively. In reality, the reticle maintains the same perspective with the target size throughout the magnification range. That means the holdover points remain the same throughout the range of magnification. For example, the 5 MOA line is at 5 MOA for all magnification settings. The downside of an FFP reticle is it appears small and thin at low power and gets thicker at high power, so it can be hard to see at the lowest settings and can cover too much target at the highest setting.

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Team Lapua’s Nancy Tompkins Wins 3rd Consecutive Western Wildcat

For the third consecutive year, Team Lapua member Nancy Tompkins has brought home the Western Wildcat International Smallbore title using Lapua Center-X .22LR ammunition.

The Western Wildcat was hosted by the Desert Sharpshooters Rifle Club March 15 – 21st at the Ben Avery Shooting Complex in Phoenix, AZ. Nancy Tompkins won the Grand Aggregate with a commanding 6392-508X (of possible 6400).

Nancy stated, “The 2021 Western Wildcat Smallbore matches were challenging, but a great time of shooting and enjoying friends. It was just a year ago that the world was shut down due to the pandemic. The 2020 Wildcat was canceled as was most everything for many months. While travel is still challenging for some and impossible for our overseas friends, we had over a dozen first time shooters to the Wildcat and thankfully many of our longtime participants. I always say that the best part of shooting is the people, and that still holds true. That includes the shooters, the workers, and the sponsors that contribute their time and/or product to make this match what it is. I would like to thank Lapua for making precision ammo that allows me and others to achieve their highest possible scores. Winning the Western Wildcat three times in a row is an honor of which I am truly thank for.”

Nancy’s Lapua Center-X .22LR ammunition is matched to her firearm at Lapua’s Rimfire Performance Center. Unique lots of ammunition are tested at 50 and 100 meters simultaneously, identifying the best performing ammunition for purchase. This service is available to all shooters who wish to gain a competitive advantage. If you are located in the U.S., schedule your testing here at either of Lapua’s Rimfire Performance Centers located in Mesa, AZ or Marengo, OH.

Lapua Monarch Cup Confirms Commitment for 2022

With ongoing travel restrictions between Canada, USA, and Mexico, the 2021 Lapua Monarch Cup Series has been postponed until 2022.

The Lapua Monarch Cup will be the must-attend event of the silhouette shooting world for 2022. Hosted in three different countries: Canada, United States and Mexico, the Lapua Monarch Cup will take place throughout the summer and fall of 2022. Competitors earn points from each match within their respective classification (Master, AAA, AA, & A), giving all shooters an opportunity for the $25,000 in cash prizes.

“In light of the continued global health challenges with COVID-19, the Monarch Cup Board of Directors made the difficult decision to postpone the Lapua Monarch Cup to 2022,” stated Monarch Cup Director, Daniel Salazer. “The uncertainty regarding international travel and the concern for the safety of our friends and competitors, led to this very disappointing decision. We vow to make the 2022 Lapua Monarch Cup an event to remember.”

“Lapua is saddened that this difficult decision had to be made, but we know it’s the right one,” stated Adam Braverman, Director of Sales and Marketing. “The board and Lapua’s top priority is of the health and safety of the international shooting community. We are excited to announce that we will continue as the Title Sponsor of the Monarch Cup for 2022.” For more information on the Lapua Monarch Cup visit lapuamonarchcup.com.

Introducing: New factory-loaded hunting cartridges

We are excited to bring forth two new top-performance hunting rounds for two very popular calibers, the .223 Rem. And the 6.5 Creedmoor.

.223 Remington with the Lapua Naturalis bullet

.223 Remington, one of the most popular cartridges, is now available with the 3,2 g / 50 gr Lapua Naturalis hunting bullet. This is the perfect cartridge choice for anyone looking for performance without wasting any meat.

The .223 Rem started out as a varmint round in the 1950ies but it has come a long way since then to become a viable choice for small game and even small deer hunting. Today, we are proud to introduce one of the most modern and innovative .223 Rem cartridges for this purpose with our .224 Naturalis projectile. It has everything a demanding small game hunter needs, superb accuracy and top-of-the-class terminal ballistic performance. As with all our Naturalis projectiles, it comes with our new AirLock technology, securing that the cartridge performance is secure from dust and outside moisture changes.

The technology of the Naturalis bullet allows for a perfect mushrooming effect, expanding the bullet diameter up to double the original, creating an adequate wound channel. With exceptional performance and amazing penetration capabilities up to 100 % of retention weight, this factory-loaded cartridge is a must-have for any .223 Rem enthusiast wanting to make fond new hunting memories.

6.5 Creedmoor with the Lapua MEGA bullet

While the 6.5 Creedmoor was originally designed for long range target shooting, it has during its short lifespan already gained a reputation as a viable hunting caliber. Lapua’s 6.5 Creedmoor range of factory-loaded cartridges is now complemented with the addition of the 6,5 mm 10,1 g / 156 gr Soft Point MEGA projectile. This hunting bullet is known for an amazing accuracy almost matching bench rest bullets, and it has established its reputation as an excellent moose hunting bullet in the Nordic countries for decades. The reliable MEGA locking holds the bullet jacket and core tightly together, even in a hard bone hit. With the soft recoil and range performance of the 6.5 Creedmoor combined with our top components, we expect this cartridge to become a favorite with red deer, fallow deer and white-tailed deer hunters.

The new Lapua cartridges will be hitting the markets in the summer of 2021.

New match grade ammunition for 6.5 Creedmoor and .260 Remington

While the 6.5 Creedmoor continues to increase in popularity in competitive shooting, there is also a growing demand for a match solution for .260 Remington. Lapua has risen to the occasion and presents new factory-loaded cartridges designed to conquer the market and outperfom the competition at ranges up to 1,000 m/yds and even beyond.

The rounds are loaded with the 8,8 gram / 136 grain Scenar-L bullet. Introduced in 2013, it has ever since become a staple midrange and long range match projectile in 6.5 mm applications.

Both calibers are C.I.P. approved. Even if the .260 Rem. cartridge has a slightly shorter max overall length compared to the 6.5 Creedmoor round, it still performs similar to the latter in terms of muzzle velocity and hit accuracy. The biggest difference between the two is that the 6.5 Creedmoor case is Small Rifle Primer while the .260 Rem. has a Large Rifle Primer pocket.

If you are looking for a podium finish in PRS, silhouette or other accuracy disciplines, Lapua’s new match grade rounds are guaranteed to help you reach your peak potential. These cartridges will also meet the high demands of Military / Law Enforcement professionals.

The new Lapua cartridges will be hitting the markets in the summer of 2021. Flight Trajectory data coming soon!
Lapua Ballistics tips: Spin drift adjustment

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

What is Spin Drift?

Spin drift (or gyroscopic drift) causes the bullet to drift slightly horizontally at long shooting distances. The direction of the drift is the same as the barrel twist rotation, i.e. in your typical right-handed rifle it is in the right hand direction. Spin drift is caused by aerodynamics forcing the bullet tip to turn slightly in the direction of rotation as the bullet tip follows its curved flight path. This rotation of the bullet is very small, usually less than 0.1 degrees, but because it affects the entire flight path, it moves the bullet slightly in the direction of the spin.

The magnitude of the spin drift is most affected by the spin rate, bullet length and flight time (bullet velocity), to a lesser extent also by air density.

How to adjust Spin Drift in Lapua Ballistics

The Spin Drift correction can be turned off in the Manage Rifle Cartridge data menu under the current weapon profile (Sight-In settings), but we recommend that you select ‘On’ and then leave it as is. In extreme long range shooting (500 m/yds and up), you can fine-tune the spin drift magnitude to match the exact spin drift tested in practice with your firearm and cartridge combination. However, this precise determination of the actual spin drift is very difficult, because the effect of even a very small wind gust is usually many times larger than the magnitude of the spin drift. Therefore, using the factory setting usually gives the most reliable result.

Lapua Ballistics Spin Drift adjustment

Our next tip will feature how to build your own reticle. Stay tuned!

Go to Lapua Ballistics main page

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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:

Lapua-Ballistics-Stability-Estimation-4

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

Lapua-Ballistics-Stability-Estimation

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

Lapua-Ballistics-Stability-Estimation

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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