Lapua Ballistics Tips: Point blank range and V0 calculation
May 25, 2020
Lapua Ballistics Tips: Point blank range and V0 calculation
We are kicking off a brand new series on our website: Lapua Ballistics app tips! Get the most out of our free of charge ballistics calculator by following our tips which we will be sharing all through year 2020. The first tips are: Utilizing Point Blank Range and V0 or Muzzle velocity calculation. The next tip will be […]
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TIP: Utilizing Point Blank Range
The Point Blank Range (PBR) feature shows the min to max distance within which the bullet will hit the predefined target area without adjusting the point of aim or scope. Knowing the PBR is useful in situations where you don’t have time to make adjustments to your scope or you don’t know the exact shooting distance – a typical situation when hunting. By calculating the PBR you can optimize your sight-in distance so that the PBR is as long as possible. We will also explain how you can “set” your scope for a distance of e.g. 170 m , even if you only have a 100 m shooting range.How to use the Point Blank Range feature in Lapua Ballistics:
- Choose your cartridge and set correct muzzle velocity and barrel twist.
- Important – make sure you have entered the correct “Line of Sight to Bore”. Line of Sight to Bore refers to the distance between center of the bore to the optical axis of the scope.
- Weather conditions don’t have significant impact on this feature. Insert the typical temperature, air pressure and humidity for your hunting area.
- Define the target hit area size in relation to the point of aim (the perfect hit), i.e. enter the height of the pipe within which the trajectory should be.
- By comparing (i.e. bracketing) values, you can optimize sight-in distance by changing it to the distance within which the bullet stays within the pipe you have entered.
- In practice, you want a sight-in distance where the highest point of the flight path touches on the top of the pipe you entered.
EXAMPLE: PBR for big game hunting cartridge
In this example, the shooter wants the bullet to hit the target (+/- 5 cm) within a 10 cm window size. If the rifle is sighted in at a distance of 100 m, the shooting distance range is 0 to 160 m without adjusting the scope or changing the point of aim. By bracketing, the optimum sight-in distance is found to be 170 m, with the shooting distance range of 0 – 200 m without adjusting the scope of changing the point of aim. The Elevation LOS column in the flight path table (below) indicates the elevation height of the bullet in relation to the line of sight. |
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Utilizing the flight path table
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Error calculation / unstable bullet
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TIP: Muzzle velocity calculation
Most ballistics programs require the muzzle velocity V (at 0 m/yds) of the bullet as the starting value for ballistic calculation. However, most chronographs have to be installed several meters/yards in front of the barrel muzzle so that the muzzle pressure and muzzle flame do not interfere with the result or damage the chronograph. With the muzzle velocity calculation function, the bullet velocity V measured at a distance of x meters/yards can be converted to the bullet velocity V at the muzzle of the barrel (at 0 m/yds). The function is only intended for short distances, less than (or maximum) 25 m/yds. Using the function:- Enter the editing mode of the cartridge you are using (pen image).
- Activate the Powder dv/dT Visible button
- Activate the Velocity V1 Visible button
- Enter the distance from the barrel muzzle to the chronograph in the Range window (unit m or yd; here 10 m) and the velocity reading by the chronograph in the V1 window (unit m/s or fps; here 730 m/s).
- The muzzle velocity of the bullet is shown in the V0 window (unit m/s or fps; here 736 m/s).
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Category
Products
The Lapua Naturalis family includes hunting cartridges in calibers:
.222 Remington
.243 Winchester
6,5×55 SE
6,5×47 Lapua
6,5 Creedmoor
7×64
7x65R
.308 Winchester
.30-06
8×57 IS
8×57 IRS
.338 Lapua Magnum
9,3 x 62
60-year-old Matti Rajala is a familiar figure at the Lapua cartridge factory, as he has been working with the company since 1981. Matti is an EDM machinist in the factory’s tooling department, and his years of experience is a unique asset to the company. Matti can also be called a product expert, because
he has used the Lapua Naturalis hunting bullets since the very launch of the product in 2002. An avid hunter, he boasts quite the collection of fired mushroomed Naturalis bullets.
“I’ve grown up around hunting, and I’ve been hunting ever since I got my hunting license at age 15. During the season I go hunting on a weekly basis, whenever I can really. I hunt mostly moose, but I also go bird hunting with my Finnish Spitz Pate. For me, Naturalis is simply the best hunting bullet. No lead residues and weight loss is minimal. I’ve shot approx. 40 moose with Naturalis, the largest of which was a 13-pointer.”
A lifetime of hunting means a fair amount of good memories, too. “It was my second season with a hunting party. I was waiting at my spot when a large moose, an 11-pointer, appeared right in front of me. It stopped at a distance of about 30 yards away, its flank straight towards me. I took aim and shot it slightly behind the shoulder. Nothing happened. The moose just stood there in the exact same spot. I thought to myself, Ok, I’m not going to shoot it twice – if I can’t hit a moose at this distance, I might as well let it walk off! Then suddenly the moose began to sway, and eventually fell dead to the ground right where it stood. And down it stayed!”
Subsonic point is now visible in Trajectory table
The feature takes into account the impact of temperature on the speed of sound.
Adjustable Spin Drift
To Activate, go to Menu -> Manage rifle / Cartridge data -> Spin Drift
Spin drift ‘ON’: Spin drift is calculated according to design methods in 6DOF.
Spin drift ‘OFF’: Spin drift calculation is disabled. Trajectory path (horizontal) is straight line.
Spin drift ‘Custom’: Spin drift multiplier can be set between 0 – 2. E.g multiplier 2.0 means 2 x normal spin drift calculated by 6DOF methods.
Custom value 0 equals to Spin Drift – Off; Custom value 1 equals to Spin Drift – On. The calculation follows the design methods in 6DOF.
Lapua Ballistics Dark theme
All the views in the app are shown in dark mode. This feature improves the usability in dark and low light conditions.
Activation: Menu -> Set Units / Settings
All data related to the calculations are summarized at the end of the table (Fig 7). You can view 7 data columns at once; to select the data you want to see, tap the white triangle in the upper right corner of your screen. You can also choose the direction of the range (Descending or Ascending) at the bottom of the screen. (Fig 8). Note: In the trajectory table, values Sg (gyroscopic stability )and Sd (dynamic stability) are visible on a range from zero to max. The Angle of Impact or AOI is a new value option, a very rare feature in ballistic calculators.
