July 5th, 2019

ELR on a Budget — Shooting One Mile with .338 LM Savage

Savage BA110 .338 Lapua magnum 1 mile

After the 2019 King of 2 Miles competition last weekend, some readers asked whether it’s possible to shoot Extreme Long Range with a regular factory rifle — a rig that costs thousandths less than the full custom 40-lb ELR beasts used by top KO2M teams. The answer is a definite yes. Here’s a story from Forum member Mark Dalzell. A few seasons back, Mark showed what can be done with a factory Savage 110 BA at extreme long range — 1760 yards (one mile). Mark did a great job with the video, which features multiple camera views so you can see the shooter and the target at the same time. Enjoy!

This video by Mark Dalzell demonstrates the long-range capabilities of the Savage 110 BA chambered in .338 Lapua Magnum. Mark took his “BadAss” rig out to the southwest Nevada desert just north of Jean Dry Lakes. He placed a 2’x3′ target way, way out there — a full mile (1760 yards) away. At that range, flight time to target was 3.75 seconds! Sighting with a Nightforce 5-22x50mm NXS scope, Mark needed a few shots to get on target, but eventually made multiple hits, using 67 MOA of elevation and 2.25 MOA left windage. You can view the hits starting at 1:56 time-mark on the video. (Mark had a second camera set up closer to the target — this displays frame in frame in the video, and if you watch carefully you can see the strikes.) The ammo was HSM 250gr HPBT match with a 3.600″ COAL. The shooting was done at 8:13 in the morning, with clear conditions, very light winds. Temp was 57°, humidity 24.5, Density Altitude 3666. Video soundtrack is La Grange by ZZ Top.

LISTEN TO MARK TALK about One Mile Shooting:
CLICK Play Button to hear Mark Dalzell TALK about his .338 LM Savage 110 BA and how he scored hits at 1760 yards.

Good Shooting Mark. That’s darn good for a factory rifle. You also had the elevation dialed in real close before the firing started! That shows a good knowledge of your ammo’s long-range ballistics. We also noticed how effective that muzzle brake was. Recoil looked about the same as an un-braked .308 Win.

.338 LM Lapua Magnum cartridge diagram

If you thought Mark’s 1760-yard shooting was impressive, Mark has produced another video that shows a session at even greater distances — out to 2300 yards. Watch Mark Dalzell Shoot at 2300 Yards.

Mark Dalzell 1760 yards mile shooting video Nevada Accurateshooter

Permalink - Videos, Shooting Skills, Tactical 3 Comments »
July 5th, 2019

Optimize Bullet RPM with Berger Twist Rate Stability Calculator

Berger twist rate calculator

Berger twist rate calculatorBerger Twist-Rate Stability Calculator
On the Berger Bullets website you’ll find a handy Twist-Rate Stability Calculator that predicts your gyroscopic stability factor (SG) based on mulitiple variables: velocity, bullet length, bullet weight, barrel twist rate, ambient temperature, and altitude. This cool tool tells you if your chosen bullet will really stabilize in your barrel.


How to Use Berger’s Twist Rate Calculator
Using the Twist Rate Calculator is simple. Just enter the bullet DIAMETER (e.g. .264), bullet WEIGHT (in grains), and bullet overall LENGTH (in inches). On its website, Berger conveniently provides this info for all its bullet types. For other brands, we suggest you weigh three examples of your chosen bullet, and also measure the length on three samples. Then use the average weight and length of the three. To calculate bullet stability, simply enter your bullet data (along with observed Muzzle Velocity, outside Temperature, and Altitude) and click “Calculate SG”. Try different twist rate numbers (and recalculate) until you get an SG value of 1.4 (or higher).

Gyroscopic Stability (SG) and Twist Rate
Berger’s Twist Rate Calculator provides a predicted stability value called “SG” (for “Gyroscopic Stability”). This indicates the Gyroscopic Stability applied to the bullet by spin. This number is derived from the basic equation: SG = (rigidity of the spinning mass)/(overturning aerodynamic torque).

Berger twist rate calculator

If you have an SG under 1.0, your bullet is predicted not to stabilize. If you have between 1.0 and 1.1 SG, your bullet may or may not stabilize. If you have an SG greater than 1.1, your bullet should stabilize under optimal conditions, but stabilization might not be adequate when temperature, altitude, or other variables are less-than-optimal. That’s why Berger normally recommends at least 1.5 SG to get out of the “Marginal Stability” zone.

In his book Applied Ballistics For Long-Range Shooting, Bryan Litz (Berger Ballistician) recommends at least a 1.4 SG rating when selecting a barrel twist for a particular bullet. This gives you a safety margin for shooting under various conditions, such as higher or lower altitudes or temperatures.

Story idea from EdLongrange. We welcome reader submissions.
Permalink Bullets, Brass, Ammo, Tech Tip 1 Comment »