264121HV291 Technical Profile © Application: Long Range Hunting

Barrel Bore Diameter: 0.256" 6.500 mm The diameter of the barrel from land to land.
Barrel Groove Diameter: 0.264" 6.710 mm The diameter of the barrel from groove to groove.
Bullet Weight: 121gr 7.8g Bullets are guaranteed to weigh within a quarter percent of the stated weight.
Bullet Length: 1.41" 35.760 mm
Secant Ogive Length: 0.67" 16.926 mm These dimensions are critical to consistent external ballistic performance and are held constant to within 0.005 mm (0.0002")
Meplat Diameter: 0.06" 1.650 mm
Min Bullet Protrusion: 0.75" 19.020 mm Add the case length to these numbers to determine the maximum and minimum cartridge overall length that is possible with this bullet.
Max Bullet Protrusion: 1.02" 26.000 mm
Bullet conforms to CIP and SAAMI for magazine length. Case and COL based on: 26 Nosler. Check the COL of your rifle for suitability with this bullet as described above. Check the magazine length of your rifle for suitability with this bullet.
Maximum M/V: 4200fps 1,280 m/s If the maximum muzzle speed is exceeded, dynamic stabilty problems may be encountered.
Minimum Impact Speed: 1600fps to 1700fps 488 m/s to 518 m/s At this impact speed, the bullet will open to at least double caliber.

Twist Rates are guidelines but the Minimum Twist must be observed 
Twist: Sg = 1.4: 7.1" / 181 mm 27.9 Calibers General hunting twist for average distances to 600 yards or 550 m. A tighter twist (smaller number) can be used.
Minimum Twist: 8" / 203.2 mm 31.3 Calibers The slowest twist required for stable flight and good terminal performance further than 890 yds or 820 m. See 'Notes' below.

Calculated Ballistic Coefficient - Standard Metro G1 profile. Based on: Cd = 0.220

BC = 0.543 Maximum M/V to 2900 fps Maximum M/V to 884 m/s Any comparison with the BC values of other manufacturers is not valid as there is currently no standard method in use between manufacturers.  These BC values are only for use in an external ballistics program. Use the three values, as given, to approximately calculate BC for your launch speed and distance. For exact numbers, shoot drop tables at the elevation and temperature for your location.
BC = 0.470 2900 fps to 1600 fps 884 m/s to 488 m/s
BC = 0.462 1600 fps to 0 fps 488 m/s to 0 m/s

Some of the Suitable Cartridges, with consideration of the above specifications:

260 Remington, 6.5 - 284 Norma, 256 Gibbs, 26 Nosler, 6.5 Creedmoor, 6.5 PRC, 6.5x47 Lapua - Use the specification sheet above to determine whether this bullet is suitable for the cartridge you want to use, if it is not listed.

NOTES
A Gyroscopic Stability (Sg) greater than 1.1 is required for stable flight with HV and HP bullets. For hunting under 600yds/550m, an Sg of up to 1.4 or more can be used. For longer distances the Sg can be decreased but never less than 1.1.
*Note that Sg increases as twist tightens.  *A 1:10" twist is tighter than a 1:12" twist within a given caliber only. *Twist rates given in caliber lengths can be compared across calibers. *Choose a bullet length best suited to your rifle twist and type of shooting.  *When a bullet is specified for a given twist rate, it can also be used in any twist that is tighter.  Using it in a slower twist than specified, is not advisable. *Some experimentation will be required to determine exact drop tables for your equipment and location.