243081SP197 Technical Profile    Application Target/Tactical

Barrel Bore Diameter: 0.237" 6.020 mm The diameter of the barrel from land to land.
Barrel Groove Diameter: 0.243" 6.170 mm The diameter of the barrel from groove to groove.
Bullet Weight: 81gr 5.3g Bullets are guaranteed to weigh within 0.25% of the stated weight.
Bullet Length: 1.11" 28.100 mm
Tangent Ogive Length: 0.54" 13.724 mm These dimensions are critical to consistent external ballistic performance and are held constant to within 0.005 mm (0.0002")
Meplat Diameter: 0.02" 0.602 mm
Min Bullet Protrusion: 0.60" 15.320 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: 0.75" 19.000 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: 3600fps 1 097 m/s If the maximum muzzle speed is exceeded, dynamic stabilty problems may be encountered.

Twist Rates are guidelines but the Minimum Twist must be observed 

Twist: Sg = 1.4: 7.4" / 187 mm or tighter 31.1 Calibers or tighter The twist required to give a calculated Sg 1.4
Minimum Twist: 8" / 203.2 mm 33.8 Calibers The slowest twist required for stable flight and the best long range tractability more than 500 yds or 460 m. See the 'Notes' below.

Calculated Ballistic Coefficient - Standard Metro G1 profile

BC = 0.405 Maximum to 2400 fps Maximum to 732 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 = 0.360 2400 fps to 1200 fps 732 m/s to 366 m/s
BC = 0.258 1200 fps to 0 fps 366 m/s to 0 m/s

Suitable Cartridges, with consideration of the above specifications:

.243" / 6 mm


A Gyroscopic Stability (Sg) greater than 1.2 is required for SP bullets. For use under 500yds/460m an Sg of up to 1.5 or even greater can be used. For distances beyond 500yds/460m, the Sg can be decreased with a slower twist, but never less than 1.2 for GSC SP bullets.
*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.