204032HV254 Technical Profile
Bore Diameter: 0.200" 5.080 mm The diameter of the barrel from land to land.
Groove Diameter: 0.204" 5.180 mm The diameter of the barrel from groove to groove.
Bullet Weight: 32gr 2.1g Bullets are guaranteed to weigh within 0.25% of the stated weight.
Bullet Length: 0.58" 14.700 mm
Ogive Length: 0.25" 6.307 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 Protrusion: 0.29" 7.470 mm Add the case length to these numbers to determine the maximum and minimum cartridge overall length that is possible with this bullet.
Max Protrusion: 0.43" 11.000 mm
Bullet conforms to CIP and SAAMI for magazine length. Check the magazine length of your rifle for suitability with this bullet.
Max Launch Speed: 4850fps 1,478 m/s If the launch speed is exceeded, dynamic stabilty problems may be encountered
Minimum Twist: 13" 65.0 Calibers in length The slowest twist required for stable flight and good long range terminal performance.
Sg = 1.5: Twist = 12.0" Twist = 57.9 Cal. in length General hunting twist requirement.
Short Range Twist: 11" or tighter 55.4 Cal/length or tighter Twist requirement if hunting distances do not exceed 150 meters.
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 = 0.148 4850 fps to 3225 fps 1,478 m/s to 983 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 = 0.126 3225 fps to 1600 fps 983 m/s to 488 m/s
BC = 0.123 1600 fps to 0 fps 488 m/s to 0 m/s

Suitable Cartridges, with consideration of the above specifications:

204 Ruger

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.