Sellier & Bellot 270Win 130Gr SP 20 Round Box

$36.99

Semi-Jacketed Soft Point bullet. A lead core with a precisely engineered jacket results from its controlled expansion and high weight retention.

Features:

  • Reliable Functioning
  • Rapid Controlled Expansion
  • Accurate

Specs:

Bullet:

Number 2929
Type Semi-Jacketed Soft Point
Weight (g) 8.4
Sectional Density (lb/in²) 0.242
Material of Jacket CuZn 10
Length (in; mm) 35.5; 902

Cartridge Case:

Casings Factory Brass
Weight (g) 24.4
Length (mm) 82.30

Ballistics:

Ballistic Coefficient (G1; G7) 0.223; 0.112
MRD (m) 171
Estimated Power Factor (kg-fps) 381.3
+P Ammunition No
Test Barrel Length (mm) 600

Velocity and Energy:

Distance (m) Muzzle 100 200 300 400
Velocity (m/s) 894 756 631 518 415
Energy (J) 3357 2401 1672 1127 723

Trajectory:

Distance (m) 50 100 200 300 400
Points of Impact (cm) -0.7 0 -12.4 -49.7 -124.3
Points of Impact MRD (cm) 1.2 3.9 -4.7 -38.2 -108.9

Additional Information:

Ballistic Coefficient Calculation: G1 = 0.0052834x / (sqrt(V0) – sqrt(Vx))

Commonly used nowadays is the ballistic coefficient (BC or G) according to Karpov (i.e. Dr. Boris Karpov, US Army Research Laboratory, 1944), which represents not only the characteristics of the shape and the weight of the bullet, but also takes into account the actual air resistance at a specific velocity.

To calculate the ballistic coefficient requires two velocities. The initial velocity (V0), and then, at a certain point on the trajectory at the distance x from the muzzle, the Vx velocity. To measure V0 directly is difficult; therefore V5 and V100 were measured, from which V0 was subsequently extrapolated. The ballistic coefficient for one hundred metres is calculated using the following formula, in which x = 100 m. Similarly this is also applicable, of course, to other distances.

The ballistic coefficient was not adjusted in accordance with the altitude and should be considered as being universal, since Sellier & Bellot’s ballistic testing laboratory is 400 m asl., which corresponds to the average altitude of the Czech Republic. A distance of one hundred metres was chosen because, at this distance, S&B also checks the accuracy of the ammunition and because this distance has long been considered as being a “hunting” distance. The actual tests were carried out in such a manner that, using the same series of ammunition, first V5 and subsequently V100 were shot from the same barrel. Since the shooting was not performed simultaneously, firing was repeated with other series and the uniformity of the results was monitored. The ammunition was always tempered to +21 ºC.

BCs are calculated to three decimal places, which is in practice is completely satisfactory. Even after correcting for the atmospheric conditions and the altitude, the weight tolerance of the bullet and its initial velocity (V0) still come into play, and of course so does the length and the wear of the specific barrel.

The entire issue is actually much broader, because, for example, on the Internet it is possible to find articles that describe differences of up to 25% from the values reported by the manufacturer and discovered in the case of overshoot.

The values specified by S&B correspond very well with reality, because the velocity at a distance of 100 metres was measured and also because it is not a result that is based on a single firing. Also the documentation provided by the Sierra Company can be accepted as being reliable. The results, however, for the reasons described in the preceding paragraph, cannot be taken as dogma.

Most Recommended Distance (MRD): The point where the trajectory crosses the line of sight for the second time. The trajectory will not exceed the line of sight  by more than 4 cm.

Disclaimer:

Manufacturers, importers, suppliers, and distributors may make changes to their products without fanfare. Such changes can lead to discrepancies between the advertised product and the actual product in inventory. While International Shooting Supplies Ltd. endeavors to correctly describe the actual product in inventory, we will not be responsible for unintentional inaccuracies in text and images of the advertised product.

Manufacturer

Sellier & Bellot

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