457305FN147 Technical Profile    Application Dangerous Game Hunting

Barrel Bore Diameter: 0.450" 11.430 mm The diameter of the barrel from land to land.
Barrel Groove Diameter: 0.457" 11.620 mm The diameter of the barrel from groove to groove.
Bullet Weight: 305gr 19.8g Bullets are guaranteed to weigh within 0.25% of the stated weight.
Bullet Length: 0.89" 22.600 mm
Conical Ogive Length 0.31" 7.800 mm These dimensions are critical to consistent external ballistic performance and are held constant to within 0.005 mm (0.0002")
Meplat Diameter: 0.24" 6.200 mm
Min Bullet Protrusion: 0.39" 9.930 mm Add the case length to these numbers to determine the maximum and minimum cartridge overall length (COL) that is possible with this bullet.
Max Bullet Protrusion: 0.59" 15.000 mm
Bullet conforms to CIP and SAAMI for magazine length. Case and COL based on:45-70. Check the COL of your rifle for suitability with this bullet as described above.
Maximum M/V: 2200fps 671 m/s If the maximum muzzle speed is exceeded, dynamic stabilty problems may be encountered.

Twist Rates are guidelines but the Minimum Twist must be observed 

Minimum Twist rate: 30" / 762 mm 66.67 Calibers For linear penetration, select a bullet that meets the minimum recommended twist rate or is tighter. See 'Notes'

Calculated Ballistic Coefficient - Standard Metro G1 profile

BC = 0.101 Maximum M/V to 1700 fps Maximum M/V to 518 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 = 0.092 1700 fps to 1200 fps 518 m/s to 366 m/s
BC = 0.107 1200 fps to 0 fps 366 m/s to 0 m/s

Suitable Cartridges, with consideration of the above specifications:

45-70, 45-70 Elko Mag, 45-90 Win


A minimum twist rate of 1:30" or tighter, is preferred for this FN bullet.
*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.