GS CUSTOM USA - Bullet Technical Profile

HOME

PRODUCTS

GALLERY

THEY SAY

284188HV289 Technical Profile © Application: Long Range Hunting

Barrel Bore Diameter: 0.277" 7.040 mm The diameter of the barrel from land to land.

Barrel Groove Diameter: 0.284" 7.210 mm The diameter of the barrel from groove to groove.

Bullet Weight: 188gr 12.2g Bullets are guaranteed to weigh within 0.25% of the stated weight.

Bullet Length: 1.86" 47.200 mm

Tangent Ogive Length: 1.03" 26.177 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: 1.10" 27.980 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: 5400fps 1 646 m/s If the maximum muzzle speed is exceeded, dynamic stabilty problems may be encountered.

Twist: Sg = 1.5: 6.0" / 156 mm 22.2 Cal. in length General hunting twist for average distances to 730 yards or 670 m. A tighter twist (smaller number) can be used.

Minimum Twist: 7" / 177.8 mm 25.3 Calibers in length The twist required for stable flight and good terminal performance further than 730 yds or 670 m. See the 'Notes' hereunder.

Minimum Impact Speed: 1600fps to 1700fps 488 m/s to 518 m/s At this impact speed, the bullet will open to at least double caliber.

Calculated Ballistic Coefficient - Standard Metro G1 profile

BC = 0.932 Maximum to 3500 fps Maximum to 1 067 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 = 0.746 3500 fps to 1600 fps 1 067 m/s to 488 m/s

BC = 0.691 1600 fps to 0 fps 488 m/s to 0 m/s

Suitable Cartridges, with consideration of the above specifications:

7 mm Long Range Hunting

NOTES

A Gyroscopic Stability (Sg) greater than 1.1 is required for stable flight with HV and HP bullets. For hunting under 730yds/670m, 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.

284188HV289 Technical Profile © Application: Long Range Hunting

Barrel Bore Diameter:	0.277"	7.040 mm	The diameter of the barrel from land to land.
Barrel Groove Diameter:	0.284"	7.210 mm	The diameter of the barrel from groove to groove.
Bullet Weight:	188gr	12.2g	Bullets are guaranteed to weigh within 0.25% of the stated weight.
Bullet Length:	1.86"	47.200 mm
Tangent Ogive Length:	1.03"	26.177 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:	1.10"	27.980 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:	5400fps	1 646 m/s	If the maximum muzzle speed is exceeded, dynamic stabilty problems may be encountered.

Twist: Sg = 1.5:	6.0" / 156 mm	22.2 Cal. in length	General hunting twist for average distances to 730 yards or 670 m. A tighter twist (smaller number) can be used.
Minimum Twist:	7" / 177.8 mm	25.3 Calibers in length	The twist required for stable flight and good terminal performance further than 730 yds or 670 m. See the 'Notes' hereunder.
Minimum Impact Speed:	1600fps to 1700fps	488 m/s to 518 m/s	At this impact speed, the bullet will open to at least double caliber.
Calculated Ballistic Coefficient - Standard Metro G1 profile
BC = 0.932	Maximum to 3500 fps	Maximum to 1 067 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 = 0.746	3500 fps to 1600 fps	1 067 m/s to 488 m/s
BC = 0.691	1600 fps to 0 fps	488 m/s to 0 m/s
Suitable Cartridges, with consideration of the above specifications:

7 mm Long Range Hunting


NOTES
A Gyroscopic Stability (Sg) greater than 1.1 is required for stable flight with HV and HP bullets. For hunting under 730yds/670m, 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.