GECO ZERO 8x57 JS 9,0g
| Manufacturer | GECO |
|---|---|
| Calibre | 8.22 mm (.324") |
| Bullet weight | 139.0 gr · 9.01 g |
| Ballistic coefficient G1 | 0.225 |
| Ballistic coefficient G7 | not published |
| Drag model used | G1 |
| Muzzle velocity | 900.0 m/s · 2953 fps |
| Muzzle energy | 3648 J · 2691 ft·lb |
| Sectional density | 0.190 |
| Form factor | i1 0.843 |
| Category | Hunting |
| Source | GECO website 2026-07-02 (verified) |
Reading these numbers
Only a G1 ballistic coefficient is published for this load, so BallisticApp solves it against the G1 drag table. G1 BC drifts with velocity — the figure below is valid near the muzzle and drops off as the bullet slows.
Muzzle energy of 3648 J (2691 ft·lb) is computed from the bullet weight and muzzle velocity above, not quoted from the catalogue. Sectional density 0.190 describes weight per unit of frontal area; divided by the ballistic coefficient it gives the form factor, which is how much drag the shape adds over the standard projectile.
Among the 44 loads of this bore diameter in the database, this one's G1 BC of 0.225 is higher than 13 of them.
Similar 8.22 mm (.324") loads
Turn this into a drop table for your rifle.
These figures are the bullet's starting point. What you actually dial depends on your rifle's zero, the air you're shooting in and the wind on the day — BallisticApp solves that on the phone, offline, using the same G1/G7 tables and this database.
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