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Winchester · Rifle

Winchester Copper Impact 270 WSM 130 gr

0.418BC (G1)
130.0gr8.42 g
980m/s3215 fps
4044J2983 ft·lb
ManufacturerWinchester
Calibre7.04 mm (.277")
Bullet weight130.0 gr  ·  8.42 g
Ballistic coefficient G10.418
Ballistic coefficient G7not published
Drag model usedG1
Muzzle velocity979.9 m/s  ·  3215 fps
Muzzle energy4044 J  ·  2983 ft·lb
Sectional density0.242
Form factori1 0.578
CategoryRifle
SourceWinchester 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 4044 J (2983 ft·lb) is computed from the bullet weight and muzzle velocity above, not quoted from the catalogue. Sectional density 0.242 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 83 loads of this bore diameter in the database, this one's G1 BC of 0.418 is higher than 50 of them.

Similar 7.04 mm (.277") 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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