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338257HV045 Technical Profile © Application: Long Range Hunting

Barrel Bore Diameter: 0.330" 8.380 mm The diameter of the barrel from land to land.

Barrel Groove Diameter: 0.338" 8.590 mm The diameter of the barrel from groove to groove.

Bullet Weight: 257gr 16.7g Bullets are guaranteed to weigh within 0.25% of the stated weight.

Bullet Length: 1.91" 48.500 mm

Secant Ogive Length: 0.99" 25.258 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: 1.08" 27.430 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: 1.42" 36.000 mm

Bullet does not conform to CIP and SAAMI for magazine length. 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.

Short Range Twist: 7.3" / 186 mm or tighter 22.2 Cal/length or tighter Twist recommended if maximum hunting distances are 300 yards or 280 m. A tighter twist (smaller number) can be used.

Twist: Sg = 1.5: 9.0" / 226 mm 27.0 Cal. in length General hunting twist for average distances to 620 yards or 570 m. A tighter twist (smaller number) can be used.

Minimum Twist: 10" / 254 mm 30.3 Calibers in length The twist required for stable flight and good terminal performance further than 620 yds or 570 m. See the 'Notes' hereunder.

Minimum Impact Speed: 1200fps to 1300fps 366 m/s to 396 m/s At this impact speed, the bullet will open to at least double caliber.

Calculated Ballistic Coefficient - G1 profile

BC = 0.855 Maximum to 2700 fps Maximum to 823 m/s BC values are calculated at standard Metro values using a G1 profile. Any comparison with the BC values of other manufacturers is not valid as there is currently no standard method in use between manufacturers. Enter these values into an external ballistics program to calculate BC for your launch speed and distance. For excact values, shoot drop tables at the elevation and temperature for your location.

BC = 0.712 2700 fps to 1200 fps 823 m/s to 366 m/s

BC = 0.581 1200 fps to 0 fps 366 m/s to 0 m/s

Suitable Cartridges, with consideration of the above specifications:

.338" Cartridges

NOTES

A Gyroscopic Stability (Sg) greater than 1.1 is required for stable flight with HV and HP bullets. For hunting under 620yds/570m, an Sg of up to 1.5 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.

338257HV045 Technical Profile © Application: Long Range Hunting

Barrel Bore Diameter:	0.330"	8.380 mm	The diameter of the barrel from land to land.
Barrel Groove Diameter:	0.338"	8.590 mm	The diameter of the barrel from groove to groove.
Bullet Weight:	257gr	16.7g	Bullets are guaranteed to weigh within 0.25% of the stated weight.
Bullet Length:	1.91"	48.500 mm
Secant Ogive Length:	0.99"	25.258 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:	1.08"	27.430 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:	1.42"	36.000 mm
Bullet does not conform to CIP and SAAMI for magazine length.			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.
Short Range Twist:	7.3" / 186 mm or tighter	22.2 Cal/length or tighter	Twist recommended if maximum hunting distances are 300 yards or 280 m. A tighter twist (smaller number) can be used.
Twist: Sg = 1.5:	9.0" / 226 mm	27.0 Cal. in length	General hunting twist for average distances to 620 yards or 570 m. A tighter twist (smaller number) can be used.
Minimum Twist:	10" / 254 mm	30.3 Calibers in length	The twist required for stable flight and good terminal performance further than 620 yds or 570 m. See the 'Notes' hereunder.
Minimum Impact Speed:	1200fps to 1300fps	366 m/s to 396 m/s	At this impact speed, the bullet will open to at least double caliber.
Calculated Ballistic Coefficient - G1 profile
BC = 0.855	Maximum to 2700 fps	Maximum to 823 m/s	BC values are calculated at standard Metro values using a G1 profile. Any comparison with the BC values of other manufacturers is not valid as there is currently no standard method in use between manufacturers. Enter these values into an external ballistics program to calculate BC for your launch speed and distance. For excact values, shoot drop tables at the elevation and temperature for your location.
BC = 0.712	2700 fps to 1200 fps	823 m/s to 366 m/s
BC = 0.581	1200 fps to 0 fps	366 m/s to 0 m/s
Suitable Cartridges, with consideration of the above specifications:

.338" Cartridges


NOTES
A Gyroscopic Stability (Sg) greater than 1.1 is required for stable flight with HV and HP bullets. For hunting under 620yds/570m, an Sg of up to 1.5 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.