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Atlas Ballistics manages 2 data types including support articles. Helps you organize, track, and share your work in 1 place for teams and solo users.

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Free Ballistic Tool

Ballistic Coefficient Calculator

Inspect sectional density and form factor using a known BC, estimate effective BC from two chronograph velocities, or browse common bullet reference values.

Calculation method

Bullet specifications

Bullet weight

Diameter

Published BC

Drag model

Pick a bullet from the reference chart below or enter your bullet’s weight, caliber diameter, and BC to inspect its sectional density, form factor, and G1/G7 equivalent.

Entered G7 BC

0.326

Your supplied value

Estimated G1 BC

0.646

Rough conversion only

Sectional density

0.287lb/in²

G1 and G7 have no universal conversion ratio. The other model is a rough estimate, not a measured BC; use manufacturer data for trajectory calculations.

Aerodynamic breakdown

G7 form factor (i)0.880

Indicative drag classUltra-low-drag match (VLD / A-Tip / LRHT)

BC formula (SD ÷ i)0.287 ÷ 0.880 = 0.326

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Bullet Ballistic Coefficient (BC) Chart

Reference G1/G7 values and sectional density for common match and hunting bullets. Verify BCs with the manufacturer; some alternate-model values are estimates. Click a row or use its Load bullet button.

Caliber	Bullet	Weight	G1 BC	G7 BC	SD
.224 (5.56 / .223)	Hornady 55 gr FMJ-BT	55 gr	0.243	0.122	0.157
.224 (5.56 / .223)	Hornady 53 gr V-MAX	53 gr	0.290	0.146	0.151
.224 (5.56 / .223)	Sierra 69 gr MatchKing	69 gr	0.301	0.154	0.196
.224 (5.56 / .223)	Hornady 75 gr ELD Match	75 gr	0.467	0.235	0.214
.224 (5.56 / .223)	Sierra 77 gr MatchKing	77 gr	0.372	0.195	0.219
.224 (5.56 / .223)	Berger 77 gr OTM Tactical	77 gr	0.374	0.192	0.219
.224 (5.56 / .223)	Hornady 88 gr ELD Match	88 gr	0.545	0.274	0.251
6mm (.243)	Hornady 87 gr V-MAX	87 gr	0.400	0.201	0.210
6mm (.243)	Nosler 95 gr Ballistic Tip	95 gr	0.379	0.191	0.230
6mm (.243)	Hornady 103 gr ELD-X	103 gr	0.512	0.258	0.249
6mm (.243)	Berger 105 gr Hybrid Target	105 gr	0.536	0.275	0.254
6mm (.243)	Hornady 108 gr ELD Match	108 gr	0.536	0.270	0.261
6mm (.243)	Berger 109 gr LRHT	109 gr	0.568	0.292	0.264
.257 (.25 Cal)	Nosler 115 gr Ballistic Tip	115 gr	0.453	0.228	0.249
.257 (.25 Cal)	Blackjack 131 gr ACE	131 gr	0.645	0.330	0.283
.257 (.25 Cal)	Hornady 134 gr ELD Match	134 gr	0.645	0.343	0.290
6.5mm (.264)	Hornady 123 gr ELD Match	123 gr	0.506	0.255	0.252
6.5mm (.264)	Berger 130 gr VLD Hunting	130 gr	0.562	0.287	0.266
6.5mm (.264)	Hornady 140 gr ELD Match	140 gr	0.646	0.326	0.287
6.5mm (.264)	Berger 140 gr Hybrid Target	140 gr	0.607	0.311	0.287
6.5mm (.264)	Hornady 143 gr ELD-X	143 gr	0.625	0.315	0.293
6.5mm (.264)	Berger 144 gr LRHT	144 gr	0.655	0.336	0.295
6.5mm (.264)	Hornady 147 gr ELD Match	147 gr	0.697	0.351	0.301
6.5mm (.264)	Hornady 153 gr A-Tip Match	153 gr	0.704	0.355	0.314
6.5mm (.264)	Berger 156 gr EOL Elite Hunter	156 gr	0.679	0.347	0.320
.277 (.270 / 6.8)	Hornady 130 gr SST	130 gr	0.460	0.232	0.242
.277 (.270 / 6.8)	Hornady 145 gr ELD-X	145 gr	0.536	0.270	0.270
.277 (.270 / 6.8)	Sierra 165 gr Tipped GameKing	165 gr	0.612	0.308	0.307
.277 (.270 / 6.8)	Berger 170 gr EOL Elite Hunter	170 gr	0.662	0.339	0.317
7mm (.284)	Nosler 140 gr AccuBond	140 gr	0.485	0.244	0.248
7mm (.284)	Hornady 162 gr ELD-X	162 gr	0.631	0.318	0.287
7mm (.284)	Hornady 175 gr ELD-X	175 gr	0.689	0.347	0.310
7mm (.284)	Berger 180 gr Hybrid Target	180 gr	0.680	0.345	0.319
7mm (.284)	Hornady 180 gr ELD Match	180 gr	0.796	0.401	0.319
7mm (.284)	Berger 195 gr EOL Elite Hunter	195 gr	0.755	0.387	0.345
.308 (.30 Cal)	Hornady 110 gr V-MAX (.300 BLK)	110 gr	0.290	0.146	0.166
.308 (.30 Cal)	Hornady 150 gr InterLock	150 gr	0.338	0.170	0.226
.308 (.30 Cal)	Nosler 165 gr AccuBond	165 gr	0.475	0.239	0.248
.308 (.30 Cal)	Sierra 168 gr MatchKing	168 gr	0.462	0.223	0.253
.308 (.30 Cal)	Sierra 175 gr MatchKing	175 gr	0.505	0.243	0.264
.308 (.30 Cal)	Hornady 178 gr ELD-X	178 gr	0.552	0.278	0.268
.308 (.30 Cal)	Berger 185 gr Juggernaut OTM	185 gr	0.552	0.283	0.279
.308 (.30 Cal)	Hornady 200 gr ELD-X	200 gr	0.597	0.301	0.301
.308 (.30 Cal)	Hornady 212 gr ELD-X	212 gr	0.663	0.336	0.319
.308 (.30 Cal)	Berger 215 gr Hybrid Target	215 gr	0.691	0.354	0.324
.308 (.30 Cal)	Hornady 220 gr Sub-X (.300 BLK)	220 gr	0.397	0.200	0.331
.308 (.30 Cal)	Hornady 225 gr ELD Match	225 gr	0.777	0.391	0.339
.308 (.30 Cal)	Hornady 230 gr A-Tip Match	230 gr	0.823	0.414	0.346
.338 Cal	Sierra 250 gr MatchKing	250 gr	0.625	0.310	0.313
.338 Cal	Hornady 285 gr ELD Match	285 gr	0.829	0.417	0.356
.338 Cal	Berger 300 gr OTM Tactical	300 gr	0.818	0.419	0.375

G1 vs G7 ballistic coefficient: which one should you use?

Every ballistic coefficient compares your bullet against a standard reference shape. The G1 standard looks like a classic flat-base hunting bullet with a blunt ogive. The G7 standard has a long boat-tail and a sleek tangent ogive that closely mirrors modern match and long-range hunting projectiles.

G1 and G7 can both produce useful predictions when paired with BC data measured for that model and velocity interval. A single averaged G1 value may fit a long boat-tail bullet less closely as it slows. For boat-tail rifle bullets at distance, use a published G7 number when available — and use our ballistic trajectory calculator to turn that BC into a full drop and wind table.

How this calculator works

Sectional density is weight in grains ÷ (7,000 × diameter²). Form factor is i = SD ÷ BC, using your supplied BC. The alternate G1/G7 value uses a rough 1.982 ratio, not a universal conversion. Chronograph mode numerically integrates 1 / (v × Cd) across compact BRL drag-curve checkpoints and corrects dry-air density for station pressure and temperature. It estimates effective BC over the measured interval, assumes level flight and still air, and supports Mach 0.8–4.

Worked example: A 140 gr, 0.264 in bullet has SD = 140 ÷ (7,000 × 0.264²) = 0.287 lb/in². With a published G7 BC of 0.326, its G7 form factor is 0.287 ÷ 0.326 = 0.880.

Ballistic coefficient
Bryan Litz, Applied Ballistics for Long Range Shooting

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Frequently asked questions

Ballistic coefficient measures how well a bullet overcomes air resistance in flight. It is the ratio of the bullet’s sectional density (mass divided by diameter squared) to its form factor (how streamlined its nose and tail are compared with a reference projectile). A higher BC means the bullet loses velocity more slowly, drops less, and drifts less in the wind.

G1 and G7 refer to the shape of the standard reference projectile used to measure drag. The G1 model is based on a flat-base, blunt-nose projectile and fits traditional hunting, pistol, and rimfire bullets well. The G7 model is based on a long, boat-tail, tangent-ogive projectile and matches how modern long-range match and hunting bullets actually decelerate across supersonic speeds.

The formula is BC = SD ÷ i, where SD is sectional density (bullet weight in grains ÷ 7,000 ÷ caliber diameter in inches squared) and i is the form factor relative to the G1 or G7 standard bullet. In the field, you can also measure effective BC by recording muzzle velocity and downrange velocity with a chronograph and solving for the drag retardation between the two points.

Because the G7 standard reference projectile is already much sleeker than the old G1 standard projectile. A modern boat-tail bullet has a form factor near 1.0 against the G7 reference (making its G7 BC close to its sectional density, around 0.25 to 0.40), whereas against the blunt G1 reference its form factor is around 0.50, making the G1 number roughly twice as large.

Yes. A G1 BC changes noticeably as the bullet slows down because a sleek boat-tail bullet does not shed speed along the same curve as a flat-base G1 standard projectile. A G7 BC stays much more constant from the muzzle all the way to the transonic zone, which is why long-range shooters prefer G7.

More free ballistic calculators

All free, all in the browser, no download needed.

Ballistic Calculator

Full trajectory table with drop, drift, velocity and energy.

Ballistic Coefficient Calculator & Chart

Estimate effective G1/G7 BC, inspect form factor, and browse bullet reference values.

Muzzleloader & Airgun Calculator

G1/G7 trajectory estimates with specialty-projectile model limitations.

Bullet Energy Calculator

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MOA to MIL Calculator

Convert MOA, MIL and inches, and get your scope clicks.

Twist Rate Calculator

Miller stability factor and the twist your bullet needs.

Bullet Stability Calculator

Sg at your velocity, plus sectional density.

Recoil Calculator & Chart

Free recoil in foot-pounds and side-by-side cartridge recoil chart.

Angle Shot Calculator

Uphill and downhill range correction with the cosine rule.

Grains to Grams

Convert bullet and powder weights both ways.

Density Altitude Calculator

Temperature, pressure and humidity turned into density altitude.

MPBR & Optimal Zero

Find a suggested zero and point-blank range for your target-zone size.

Zero Calculator

Sight in at 25 yd for a 100 yd zero, and compare 36, 50 and 100 yd zeros.