Updated August 2026. This calculator models real trajectory physics using the G1 drag standard. Every figure is a starting point for load development, not a substitute for confirming your own drops on paper.

A Blackout ballistics calculator has to answer one question honestly: where does the bullet actually land. Static charts give you typical figures for typical rifles, which is useful right up until your barrel, your load or your zero differs from the assumptions. This tool computes the trajectory for your exact setup: pick the cartridge and load, set your barrel length, zero distance and optics height, and it returns velocity, energy, drop and flight time out to 300 yards.

How to read the numbers

Drop is measured against your line of sight, not the bore. A positive figure means the bullet is above your crosshair, which is normal between the muzzle and the zero on a subsonic load, because the barrel has to be angled up steeply to reach the target at all. A negative figure means hold over.

Energy is the kinetic figure everyone quotes and the one most often misread. It tells you nothing about whether the bullet expands. A 342gr subsonic carrying 800 ft lbs and a 5.56 carrying the same number behave completely differently on impact, because the heavy slow bullet delivers its energy through mass and frontal area rather than velocity. Our 8.6 Blackout ballistics chart covers why the 1:3 twist matters more than the energy column.

Time of flight is the number hunters underuse. At 200 yards a subsonic load takes roughly six tenths of a second to arrive. Game moves in that time, which is a large part of why quiet loads have a shorter ethical range than their energy suggests.

Why barrel length changes less than you think

Feed any subsonic load through this Blackout ballistics calculator at 8 inches and again at 16 inches and the velocity barely moves. That is not a modelling shortcut, it is the design. Subsonic ammunition is loaded to stay under the speed of sound in any barrel, roughly 1,125 fps at sea level, so manufacturers cap velocity deliberately. Extra barrel buys you almost nothing.

Supersonic loads behave normally, gaining roughly 20 fps per inch until the powder finishes burning, around 9 inches in 300 Blackout and around 8 in 8.6 Blackout. Past that the curve flattens hard. The practical consequence is that a short suppressed rifle gives up far less than shooters expect, which is the whole argument in our 300 Blackout barrel length guide.

Subsonic and supersonic never share a zero

Run the calculator twice, once with a subsonic load and once with a supersonic, at the same zero distance. Compare the 50 yard rows. The gap is often several inches, and it is the single most common cause of unexplained misses in these cartridges. Record both zeroes, mark your magazines, and confirm on paper before hunting. The full explanation lives in our subsonic versus supersonic guide.

What this calculator assumes

Honest tools state their assumptions. This one models a point mass trajectory using the G1 drag standard at sea level with a standard atmosphere, no wind and no Coriolis effect. Ballistic coefficients for the preset loads are typical published figures for that bullet class, and you can override them in the advanced inputs when you know your exact projectile.

Three things will move your real results away from these numbers. Altitude and temperature change air density, and thin mountain air flattens trajectory noticeably. Your chronograph almost never matches the box, because published velocities come from test barrels. And wind, which this tool does not model, dominates at the ranges where subsonic loads are already marginal. Treat the output as the starting point, then confirm with a chronograph and a target.

Frequently asked questions

How accurate is this Blackout ballistics calculator?

The trajectory solver uses the same G1 drag model that commercial ballistic software runs on, and its output matches published factory drop tables closely when fed matching inputs. Accuracy depends on your inputs, particularly muzzle velocity and ballistic coefficient. Feed it a chronographed velocity and the correct BC for your projectile and it will be close. Feed it box figures and expect the usual box figure optimism.

What zero distance is best for 300 Blackout?

For supersonic use, 100 yards is the practical standard and keeps you within a few inches out to 200. For subsonic work, 50 yards suits woods ranges better because it flattens the near trajectory where those loads are actually used. Run both in the calculator and compare the columns.

Why does the subsonic load show the bullet above my crosshair?

Because it must arc to reach the zero. A subsonic bullet drops roughly 17 inches over 100 yards, so the barrel points meaningfully upward relative to your sight line and the bullet crosses that line twice. Between those crossings it flies above your point of aim.

Does this work for 338 ARC or other cartridges?

The physics engine is caliber agnostic, so entering your own muzzle velocity, ballistic coefficient and bullet weight in the advanced inputs will model any centerfire load. The presets cover the Blackout family. For how 8.6 compares against the newer Hornady cartridge, see our 8.6 Blackout vs 338 ARC breakdown.

Why is my chronograph slower than the calculator preset?

Preset velocities are published factory figures, usually recorded from longer test barrels under ideal conditions. Real rifles run slower, and cold weather slows them further. Chronograph your load, type that number into the muzzle velocity field, and the drop column becomes genuinely yours.

Ready to shoot the numbers rather than read them? Our 8.6 Blackout ammo and 300 Blackout ammo shelves carry the loads modelled above, and the 300 Blackout ballistics chart gives the same data in reference table form. For the underlying drag standard, the ballistic coefficient entry is a useful primer, and Hornady’s ballistic calculators are a good cross check.