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264128HV280 Technical Profile © Application: LRH

Bore Diameter: 0.256" 6.500 mm The diameter of the barrel from land to land.

Groove Diameter: 0.264" 6.710 mm The diameter of the barrel from groove to groove.

Bullet Weight: 127gr 8.2g Bullets are guaranteed to weigh within 0.25% of the stated weight.

Bullet Length: 1.57" 39.857 mm

Secant Ogive Length: 0.85" 21.516 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: 0.93" 23.610 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: 1.18" 30.000 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: 4000fps 1,219 m/s If the launch speed is exceeded, dynamic stabilty problems may be encountered

Minimum Twist: 7" / 177.8 mm 27.4 Calibers in length The slowest twist required for stable flight and good long range terminal performance more than 660 yds / 610 m.

Twist: Sg = 1.5: 6.0" / 165 mm 25.4 Cal. in length General hunting twist for average distances of 320 yards or 300 m.

Short Range Twist: 5.9" / 149 mm or tighter 22.9 Cal/length or tighter Twist recommended if hunting distances do not exceed 160 yards or 150 m.

Minimum Impact Speed: 1600fps 488 m/s At this impact speed, the bullet will open to at least double caliber.

Calculated Ballistic Coefficient - G1 profile

BC = 0.607 4000 fps to 2800 fps 1,219 m/s to 853 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 = 0.537 2800 fps to 1600 fps 853 m/s to 488 m/s

BC = 0.532 1600 fps to 0 fps 488 m/s to 0 m/s

Suitable Cartridges, with consideration of the above specifications:

.264" calibers LRH

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.

264128HV280 Technical Profile © Application: LRH
264128HV280 Technical Profile © Application: LRH
Bore Diameter:	0.256"	6.500 mm	The diameter of the barrel from land to land.
Groove Diameter:	0.264"	6.710 mm	The diameter of the barrel from groove to groove.
Bullet Weight:	127gr	8.2g	Bullets are guaranteed to weigh within 0.25% of the stated weight.
Bullet Length:	1.57"	39.857 mm
Secant Ogive Length:	0.85"	21.516 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:	0.93"	23.610 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:	1.18"	30.000 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:	4000fps	1,219 m/s	If the launch speed is exceeded, dynamic stabilty problems may be encountered
Minimum Twist:	7" / 177.8 mm	27.4 Calibers in length	The slowest twist required for stable flight and good long range terminal performance more than 660 yds / 610 m.
Twist: Sg = 1.5:	6.0" / 165 mm	25.4 Cal. in length	General hunting twist for average distances of 320 yards or 300 m.
Short Range Twist:	5.9" / 149 mm or tighter	22.9 Cal/length or tighter	Twist recommended if hunting distances do not exceed 160 yards or 150 m.
Minimum Impact Speed:	1600fps	488 m/s	At this impact speed, the bullet will open to at least double caliber.
Calculated Ballistic Coefficient - G1 profile
BC = 0.607	4000 fps to 2800 fps	1,219 m/s to 853 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 = 0.537	2800 fps to 1600 fps	853 m/s to 488 m/s
BC = 0.532	1600 fps to 0 fps	488 m/s to 0 m/s
Suitable Cartridges, with consideration of the above specifications:

.264" calibers LRH


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.