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270130HV191 Technical Profile © Application: General Hunting

Barrel Bore Diameter: 0.270" 6.860 mm The diameter of the barrel from land to land.

Barrel Groove Diameter: 0.277" 7.040 mm The diameter of the barrel from groove to groove.

Bullet Weight: 130gr 8.4g Bullets are guaranteed to weigh within 0.25% of the stated weight.

Bullet Length: 1.29" 32.880 mm

Tangent Ogive Length: 0.62" 15.821 mm These dimensions are critical to consistent external ballistic performance and are held constant to within 0.005 mm (0.0002")

Meplat Diameter: 0.09" 2.200 mm

Min Bullet Protrusion: 0.70" 17.690 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: 0.98" 25.000 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: 4200fps 1,280 m/s If the maximum muzzle speed is exceeded, dynamic stabilty problems may be encountered.

Short Range Twist: 7.7" / 196 mm or tighter 28.6 Cal/length or tighter Twist recommended if average hunting distances are 260 yards or 240 m. A tighter twist can be used.

Twist: Sg = 1.5: 8.0" / 208 mm 30.4 Cal. in length General hunting twist for average distances to 510 yards or 470 m. A tighter twist can be used.

Minimum Twist: 9" / 228.6 mm 33.3 Calibers in length The twist required for stable flight and good terminal performance further than 510 yds or 470 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 = 0.407 4200 fps to 2900 fps 1,280 m/s to 884 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 = 0.367 2900 fps to 1600 fps 884 m/s to 488 m/s

BC = 0.373 1600 fps to 0 fps 488 m/s to 0 m/s

Suitable Cartridges, with consideration of the above specifications:

270 Win, 270 WSM, 270 Wea, 277GS

NOTES

A Gyroscopic Stability (Sg) greater than 1.1 is required for stable flight with HV and HP bullets. For hunting at average 510yds/470m, 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.

270130HV191 Technical Profile © Application: General Hunting

Barrel Bore Diameter:	0.270"	6.860 mm	The diameter of the barrel from land to land.
Barrel Groove Diameter:	0.277"	7.040 mm	The diameter of the barrel from groove to groove.
Bullet Weight:	130gr	8.4g	Bullets are guaranteed to weigh within 0.25% of the stated weight.
Bullet Length:	1.29"	32.880 mm
Tangent Ogive Length:	0.62"	15.821 mm	These dimensions are critical to consistent external ballistic performance and are held constant to within 0.005 mm (0.0002")
Meplat Diameter:	0.09"	2.200 mm
Min Bullet Protrusion:	0.70"	17.690 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:	0.98"	25.000 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:	4200fps	1,280 m/s	If the maximum muzzle speed is exceeded, dynamic stabilty problems may be encountered.
Short Range Twist:	7.7" / 196 mm or tighter	28.6 Cal/length or tighter	Twist recommended if average hunting distances are 260 yards or 240 m. A tighter twist can be used.
Twist: Sg = 1.5:	8.0" / 208 mm	30.4 Cal. in length	General hunting twist for average distances to 510 yards or 470 m. A tighter twist can be used.
Minimum Twist:	9" / 228.6 mm	33.3 Calibers in length	The twist required for stable flight and good terminal performance further than 510 yds or 470 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 = 0.407	4200 fps to 2900 fps	1,280 m/s to 884 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 = 0.367	2900 fps to 1600 fps	884 m/s to 488 m/s
BC = 0.373	1600 fps to 0 fps	488 m/s to 0 m/s
Suitable Cartridges, with consideration of the above specifications:

270 Win, 270 WSM, 270 Wea, 277GS


NOTES
A Gyroscopic Stability (Sg) greater than 1.1 is required for stable flight with HV and HP bullets. For hunting at average 510yds/470m, 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.