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256065HV200 Technical Profile © Application: General Hunting

Bore Diameter: 0.250" 6.350 mm The diameter of the barrel from land to land.

Groove Diameter: 0.256" 6.500 mm The diameter of the barrel from groove to groove.

Bullet Weight: 65gr 4.2g Bullets are guaranteed to weigh within 0.25% of the stated weight.

Bullet Length: 0.70" 17.900 mm

Secant Ogive Length: 0.20" 5.148 mm These dimensions are critical to consistent external ballistic performance and are held constant to within 0.005 mm (0.0002")

Meplat Diameter: 0.20" 5.000 mm

Min Bullet Protrusion: 0.27" 6.760 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: 0.55" 14.000 mm

Bullet conforms to CIP and SAAMI for magazine length. Check the magazine length of your rifle for suitability with this bullet.

Maximum M/V: 3000fps 914 m/s If the launch speed is exceeded, dynamic stabilty problems may be encountered

Minimum Twist: 15" / 381 mm 60.0 Calibers in length The slowest twist required for stable flight and good long range terminal performance.

Twist: Sg = 1.5: 13.0" / 338 mm 53.2 Cal. in length General hunting twist for average distances.

Short Range Twist: 13.5" / 344 mm or tighter 54.2 Cal/length or tighter Twist recommended if hunting distances do not exceed 150 meters/yards.

Minimum Impact Speed: 1400fps 427 m/s At this impact speed, the bullet will open to at least double caliber.

Calculated Ballistic Coefficient - G1 profile

BC = 0.076 3000 fps to 2200 fps 914 m/s to 671 m/s BC values are calculated at standard Metro values and serve as a comparison between GSC bullets. Any comparison with the BC values of other manufacturers is not valid as there is currently no standard method in use between manufacturers.

BC = 0.084 2200 fps to 1400 fps 671 m/s to 427 m/s

BC = 0.108 1400 fps to 0 fps 427 m/s to 0 m/s

Suitable Cartridges, with consideration of the above specifications:

25-20Win, 25-35Win, 257 Roberts, 256 Win Mag, 25Rem

NOTES

A Gyroscopic Stability (Sg) greater than 1.1 is required for stable flight with HV and HP bullets. For hunting under 500m, 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.

256065HV200 Technical Profile © Application: General Hunting

Bore Diameter:	0.250"	6.350 mm	The diameter of the barrel from land to land.
Groove Diameter:	0.256"	6.500 mm	The diameter of the barrel from groove to groove.
Bullet Weight:	65gr	4.2g	Bullets are guaranteed to weigh within 0.25% of the stated weight.
Bullet Length:	0.70"	17.900 mm
Secant Ogive Length:	0.20"	5.148 mm	These dimensions are critical to consistent external ballistic performance and are held constant to within 0.005 mm (0.0002")
Meplat Diameter:	0.20"	5.000 mm
Min Bullet Protrusion:	0.27"	6.760 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:	0.55"	14.000 mm
Bullet conforms to CIP and SAAMI for magazine length.			Check the magazine length of your rifle for suitability with this bullet.
Maximum M/V:	3000fps	914 m/s	If the launch speed is exceeded, dynamic stabilty problems may be encountered
Minimum Twist:	15" / 381 mm	60.0 Calibers in length	The slowest twist required for stable flight and good long range terminal performance.
Twist: Sg = 1.5:	13.0" / 338 mm	53.2 Cal. in length	General hunting twist for average distances.
Short Range Twist:	13.5" / 344 mm or tighter	54.2 Cal/length or tighter	Twist recommended if hunting distances do not exceed 150 meters/yards.
Minimum Impact Speed:	1400fps	427 m/s	At this impact speed, the bullet will open to at least double caliber.
Calculated Ballistic Coefficient - G1 profile
BC = 0.076	3000 fps to 2200 fps	914 m/s to 671 m/s	BC values are calculated at standard Metro values and serve as a comparison between GSC bullets. Any comparison with the BC values of other manufacturers is not valid as there is currently no standard method in use between manufacturers.
BC = 0.084	2200 fps to 1400 fps	671 m/s to 427 m/s
BC = 0.108	1400 fps to 0 fps	427 m/s to 0 m/s
Suitable Cartridges, with consideration of the above specifications:

25-20Win, 25-35Win, 257 Roberts, 256 Win Mag, 25Rem


NOTES
A Gyroscopic Stability (Sg) greater than 1.1 is required for stable flight with HV and HP bullets. For hunting under 500m, 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.