Understanding the Maximum Ordinate Trajectory Chart
The Maximum Ordinate Trajectory Chart is a ballistic reference tool that shows the highest point a projectile reaches above the line of sight during its flight. For the 168 grain projectile—most commonly associated with the Sierra MatchKing or similar precision bullets in .30 caliber rifles—this chart maps trajectory data across distances so shooters can dial in their optics without guessing at holdovers. You'll find these charts in PDF format from several sources. Sierra Bullets publishes theirs online, and you can download the 168 grain Maximum Ordinate Trajectory Chart directly from their website under the ballistics resources section. Hornady and Berger also maintain similar trajectory tables for their 168 grain offerings, though they present the data differently—Hornady uses a different ordinate system while Berger provides both Maximum Ordinate and Zero-to-Zero trajectory data. The basic workflow is straightforward. You load your rifle with a 168 grain bullet using your specific powder charge and seating depth. Then you sight in at your chosen distance, typically 100 yards for precision shooting applications. After that, you reference the Maximum Ordinate Trajectory Chart to understand how high the bullet rises above your line of sight between your zero distance and any longer target range. This matters because if your bullet peaks at 3 inches above LOS at 200 yards but your vital zone on an animal or target is only 8 inches wide, you need to know exactly where that peak occurs so you don't overshoot on the up-range side of your zero.
I ran into a real problem last year when shooting extended distances at a competition. I had zeroed my 168 grain Sierra at 100 yards and was using the Maximum Ordinate chart to plan my holdouts. The chart showed the bullet crossing the line of sight again somewhere around 300 yards. But when I actually shot there, the impact was consistently 4 inches high. Turns out my muzzle velocity was about 50 fps slower than what the chart assumed based on the typical BC and velocity inputs for that bullet. The chart I was using had a reference velocity that didn't match my setup. I went back and recalculated using my actual chronograph readings, then adjusted the ordinate values manually by scaling the drop relative to the velocity difference. It took maybe 20 minutes to redo the chart calculations, but it saved me from wasting a few hundred rounds trying to figure out what was going wrong. Now I always verify my velocity before trusting any published chart, especially for marginal BC bullets where small velocity differences compound quickly. One thing most people miss about Maximum Ordinate charts is that they tell you where the bullet is highest, but they don't tell you when it crosses back down through your line of sight on the way to the target. That second crossing point is just as important for ethical shots on game or precise shot placement. A common mistake is seeing that the bullet rises 2 inches at 200 yards and assuming you need to hold 2 inches low the entire time between 100 and 300 yards. In reality, the hold changes continuously, and you need the full trajectory data, not just the maximum ordinate point, to know your actual holdover at each interval. Another counter-intuitive detail is that the maximum ordinate doesn't always occur halfway between your zero and your longer reference point. With a 100-yard zero and 300-yard secondary reference, the peak might be closer to 225 yards or even 250 yards depending on the ballistics coefficient, muzzle velocity, and sight height. The exact location shifts with every variable change, which is why a chart generated specifically for your load matters more than a generic one pulled from a bullet manufacturer's catalog.
The main limitation of Maximum Ordinate Trajectory Charts is that they are load-specific. If your environmental conditions change—temperature swings, altitude differences, or even a slightly different barrel length than what was used to generate the chart—the data becomes less reliable. At distances beyond 500 yards, atmospheric variables dominate over the minor chart inaccuracies, but between 200 and 400 yards, which is where most precision shooting happens, those chart details actually matter. Some shooters just use external ballistics software instead, which lets you input real-time weather and load data and generates dynamic trajectory models. Programs like Strelok Pro or Applied Ballistics do this, though they require a bit more setup time and a good understanding of your rifle's specific performance envelope. If you're working with the 168 grain Sierra MatchKing specifically, I'd recommend generating your own chart rather than relying solely on published data. It takes maybe an afternoon of shooting and recording velocities, but the payoff in accuracy at range is significant. Start with your zero distance, shoot groups at 200, 300, 400, and 500 yards while recording your actual impacts, then feed that data into a ballistic calculator to see where your actual maximum ordinate falls compared to the published chart. You'll likely find small but meaningful differences that affect your hold strategy.
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