Ballistics Chart & Calculator: 5.56 vs 300 BLK vs .308 Drop

Ballistics Chart: 5.56 vs .300 BLK vs .308 by Range

Drop figures use a 50-yard zero for 5.56 and .300 BLK, and a 100-yard zero for .308. Velocities and energies are from common factory loads at typical chronographed muzzle velocities; your specific barrel and lot will vary by 50-100 fps. For exact numbers, use the calculator below.

Takeaway: 5.56 stays supersonic to ~650 yards from a 16" barrel; .300 BLK supersonic loads run out of energy past 300 yards; .308 Match holds 1,000+ ft-lbs to 800 yards and stays supersonic past 1,000.

What is External Ballistics?

External ballistics is the study of bullet behavior after leaving the barrel. Once the projectile exits the muzzle, it's subject to gravity, air resistance, and wind. These forces cause the bullet to drop below your line of sight and drift laterally in crosswinds.

Understanding these forces lets you predict where your bullet will impact at any distance. This knowledge is essential for making accurate shots beyond close range, whether you're shooting steel at 300 yards or hunting at 400.

Understanding Ballistic Coefficient (BC)

The ballistic coefficient measures how well a bullet resists air drag. A higher BC means the bullet retains velocity better, drops less, and drifts less in wind. BC depends on bullet weight, diameter, and shape.

G1 vs G7 Drag Models

Bullets are compared against standard projectile shapes. G1 is the traditional reference based on a flat-base bullet from the 1800s. G7 is based on a modern boat-tail bullet and is more accurate for today's projectiles.

• G1: Most commonly published. Works well for flat-base and shorter-range calculations. Most manufacturer specs use G1.
• G7: More accurate for boat-tail bullets at extended range. Better models transonic/supersonic transition. Preferred by precision shooters.

For practical purposes under 600 yards with quality ammunition, G1 data works fine. For precision work beyond 600 yards, G7 values provide better accuracy. High-BC match bullets are where this matters most: the 6.5 Creedmoor 140gr ELD Match (0.584 G1) stays supersonic past 1,400 yards, while a typical 5.56 62gr load (0.304 G1) goes transonic around 800.

Environmental Factors

Air density affects how much drag the bullet experiences. Lower air density means less drag, so the bullet retains velocity better and drops less.

Altitude

Higher altitude means lower air pressure and density. At 5,000 feet, air density is about 85% of sea level. This reduces drag and can change your drop by several inches at long range. Shooters in Denver or Salt Lake City will notice their rifles shoot flatter than at sea level.

Temperature

Hot air is less dense than cold air. A 40-degree temperature swing can change point of impact by 1-2 inches at 300 yards. If you zero at 70F, expect to shoot slightly high on a 100F summer day and low in 30F winter conditions.

Humidity

Water vapor is lighter than the nitrogen and oxygen it displaces, so humid air is actually less dense. However, the effect is small, typically less than 1% change in air density. You can usually ignore humidity unless you're doing precision work at extreme range.

Using Your Ballistic Data

Holdover vs Turret Adjustments

There are two ways to compensate for bullet drop: hold over the target with your reticle, or dial your turret to move the point of impact up.

• Holdovers: Faster for dynamic shooting. Use BDC reticle marks or estimate hold based on target size. Works best inside 400 yards where drops are manageable.
• Turret adjustments: More precise. Dial the exact MOA/MRAD correction and aim center. Essential for precision work beyond 400 yards.

MOA vs MRAD

Both are angular measurements used to quantify adjustments. Neither is inherently better: choose based on your optic.

• MOA (Minute of Angle):1 MOA = 1.047" at 100 yards (roughly 1" per 100 yards). Common on American scopes. Typical clicks: 1/4 MOA or 1/2 MOA.
• MRAD (Milliradian):1 MRAD = 3.6" at 100 yards. Popular in military and long-range precision. Typical clicks: 0.1 MRAD. Math is simpler (base-10 system).

Creating a Dope Card

A "dope card" is a quick-reference chart of your drop and drift corrections at various distances. Use the calculator above to generate your data, then record it on a card taped to your stock or stored in a scope cover.

Verify your calculated dope at the range. Real-world performance may vary slightly from calculated values due to lot-to-lot ammo variation, chronograph accuracy, and shooting conditions. A real muzzle velocity from a shooting chronograph is the single biggest accuracy unlock for the calculator above; box-velocity numbers routinely miss true MV by 50-100 fps.

Limitations & Accuracy

This calculator uses a point-mass trajectory model with atmospheric corrections. It provides accurate predictions for most shooting scenarios but has limitations:

• Doesn't account for spin drift (significant only beyond 800+ yards)
• Doesn't model Coriolis effect (relevant only for extreme long range 1000+ yards)
• Assumes constant wind speed and direction (real wind is variable)
• BC values are approximations: actual performance varies by lot

For practical rifle shooting to 600 yards, these limitations are negligible. Always verify your data at the range before relying on it in the field.

Recommended Optics for Long-Range Shooting

Precision at distance requires quality glass. These optics offer the turret tracking and reticle systems discussed above. For a broader comparison, see our best LPVO guide or the zeroing guide to dial in your new optic.

Match Ammunition for Consistent Ballistics

Ballistic calculations are only as good as your ammo consistency. Match-grade loads minimize lot-to-lot velocity variation. See our 5.56 ammo selection guide and best .308 ammo guide for detailed load comparisons. The .30-06 vs .308 comparison breaks down how the two .30-caliber loads differ on velocity, energy, and recoil.