Compare up to four loads side by side and see exactly which one drifts less — in a mild wind, in a heavy wind, and in the switching tailwind that decides most PRS and NRL Hunter stages.
Pick a caliber, choose your bullet, enter your muzzle velocity. No account needed.
What this tool answers
A normal ballistic calculator solves one load at a time. To compare two bullets you have to solve one, screenshot it, solve the other, and compare pictures on your phone. Small differences get lost, and the comparison that matters most — how each bullet behaves when the wind changes — never gets made at all.
This tool solves every load at once, under the same conditions, and shows you three things a trajectory table can’t:
Switch swing. How far your impact moves across a full wind switch, holding dead centre. Shown in inches against the actual width of your target, so you can see at a glance whether a load stays on the plate or has to be chased.
Wind you can misread. How many mph you can misjudge the wind by and still hit. This is the most useful number in the tool, because it tells you whether a load is realistically shootable under a par time rather than just how it performs when your call is perfect.
Transonic margin. Retained velocity and Mach number at every distance, flagged amber below Mach 1.2. Two bullets can look similar on drift and be very different propositions at 1100 yards.
How to use it
1. Name your rifle and pick your bullet. Select a caliber, then a bullet from the shared LoadDevelopment bullet database — the same database behind all the tools on this site. The BC fills in automatically, and stays editable if you’ve measured your own.
2. Enter your muzzle velocity. Use a chronographed average if you have one. Velocity matters as much as BC in a switch, so a guessed number will give you a misleading comparison.
3. Set your conditions. Altitude and temperature. Thin air means less drift, so a comparison run at sea level will overstate what you’ll see at 5000 feet.
4. Set your target size. Default is 2 MOA, which is roughly standard for PRS stages. Change it to match what you’re actually shooting.
5. Add loads to compare. Load one is your baseline. Every other load shows its difference against it — green means less drift.
Reading the results
The switch window at the top is the important one. Each load is drawn as a bar spanning the two impact positions at either end of the wind switch, laid over your target face at true relative scale. A bar that stays inside the circle is a load you can hold centre with. A bar that runs past the edge is a load you’ll be chasing.
The delta columns in the drift tables show each load’s difference against your baseline, so you don’t have to do arithmetic between two tables.
Amber velocity figures mean that load has dropped below Mach 1.2 at that distance and is entering transonic, where groups typically open up and any ballistic solution becomes less reliable.
Why the switching tailwind scenario is included
Most shooters model a full-value crosswind and stop there. The scenario that quietly costs the most points is a wind from behind that swings across six o’clock — because the crosswind component of a tailwind builds far faster than it looks like it should.
A 12 mph wind sitting just 15° off six o’clock — a flag that appears to be hanging straight back at you — is already delivering 3.1 mph of crosswind. When it swings 15° the other way, that crosswind reverses. At 700 yards, a 6.5 Creedmoor with a 140gr Hybrid moves 19 inches across that switch, on a plate 14.7 inches wide.
That’s why the third scenario exists, and why it’s free to use without an account.
Read the full breakdown: why switching tailwinds cost more points than a full-value crosswind →
Example: the same switch across common cartridges
A 12 mph wind swinging 45° either side of six o’clock, at sea level. Compare each row against the plate width at the bottom.
| Load | 500 yd | 700 yd | 900 yd |
|---|---|---|---|
| 6.5 PRC · 147gr ELD-M @ 2950 | 20.0″ | 41.3″ | 72.0″ |
| 6.5 Creedmoor · 140gr Hybrid @ 2750 | 25.0″ | 52.0″ | 91.6″ |
| 6 Dasher · 109gr LRHT @ 2900 | 25.1″ | 52.5″ | 92.9″ |
| .308 Win · 175gr SMK @ 2600 | 37.2″ | 79.4″ | 144.8″ |
| 2 MOA plate width | 10.5″ | 14.7″ | 18.8″ |
Note that the 6 Dasher matches the 6.5 Creedmoor almost exactly despite a much lower BC — its extra velocity buys back what the lighter bullet gives away. Run your own numbers above rather than assuming BC alone decides it.
Frequently Asked Questions
Yes. Two loads with every metric included — all three wind scenarios, the switch window, and every table. A free account raises it to four loads and lets you save comparisons.
It depends on both BC and velocity, and the answer changes with distance. A higher BC bullet at lower velocity can drift more at short range and less at long range than a lighter, faster one. That’s why this tool exists — run your actual loads rather than comparing BC values on paper.
Both. G7 is used by default where a G7 value exists, since it models modern boat-tail bullets more accurately. You can switch to G1 per load. Note that G1 and G7 values are not interconvertible with a fixed ratio.
It runs the same solver as BallistX — point-mass RK4 integration with full three-axis relative-velocity drag. Solve the same load here and in the ballistic calculator and you’ll get the same numbers.
Both are effectively identical at either end of a wind switch, so they shift every load by the same amount and never change a comparison. Including them would add a constant to every column without changing which bullet wins. For an absolute firing solution that does include them, use the ballistic calculator.
Yes. Set your target size to the vital zone you’re working with — many NRL Hunter shooters use a fixed inch value rather than MOA — and the on-target verdict updates accordingly.
Related tools:
- Ballistic Calculator — full firing solution and printable dope card for the load you pick
- Bullet BC Database — G1 and G7 values for every bullet in this tool
- Twist Rate Calculator — check stability before committing to a high-BC bullet
- LoadForge — build the load once you’ve chosen the bullet