Calculating lead on moving targets

One of the most challenging stages of the Bianchi Cup for newcomers to the sport is the Mover – I wrote about the Mover extensively last year in my run up to the match. One of the biggest concerns people have about the mover is “how much” is enough lead at what distances. Thankfully, all the distances in Bianchi Cup are known quantities, so it’s easy to calculate the approximate amount of lead you’ll need, as long as you know the velocity of your round.

The target on the mover is a standard NRA AP-1 target, which on the mover will travel 60 feet in 6 seconds, meaning it has a lateral speed of 10 feet per second. The dimensions of an AP-1 target are a 4 inch x-ring, an 8 inch 10 ring, and a 12 inch 8 ring with the rest of the target being the 5 ring (see image link). I’m going to run these calculations assuming that your bullet’s speed is 850 fps, which is fast enough to make the power factor using 158 grain (for .38s) or 147 grain (for 9mm and Super). If your bullet is going 850 feet per second, it will cover the 10 yards to the target in 0.035 seconds. In that 0.035 seconds, the target will have moved 0.35 feet, or 4.2 inches. That means at the 10 yard stage, you’ll need to hold in the area between the 10 ring and the 8 round to “aim” for the x-ring.

A couple of caveats before I get into the longer ranges: these are approximate amounts of hold. I’m not taking into account the bullet’s loss of velocity over distance, nor am I taking into account the angular distance between shooter and target when the Mover is at an angle to the shooter. Because of other uncontrolled variables such as recoil, wind, and shooter error, the goal of this post is to provide the shooter with a “point of aim” when they’re engaging the Mover at Bianchi Cup. Each measurement is a link to a picture of the point of aim.

  • 10 yards – Bullet flight time: 0.035 seconds. Amount of lead: 4.2 inches
  • 15 yards – Bullet flight time: 0.053 seconds. Amount of lead: 6.4 inches
  • 20 yards – Bullet flight time: 0.071 seconds. Amount of lead: 8.5 inches
  • 25 yards – Bullet flight time: 0.088 seconds. Amount of lead: 10.6 inches

Savvy shooters just noticed that at 850 FPS you’re going to be holding off the paper at 25 yards, which could present a problem in “hold” since you’ve lost your concrete aiming point. One of the best tricks I’ve heard for this is to hold the width of your front sight off the target at 25 yards.

In the linked images, the “hold points” are only on one side of the target – when it’s moving from right to left, use the ones in the links. When the target is going from left to right, hold on the other side of the target in the same spot. To decrease the amount of lead necessary, use a faster projectile. At 25 yards, upping your bullet speed to 1100 FPS decreases the amount of lead to 8 inches, which means that you’re again holding “on the paper”. A 115 grain bullet at 1100 FPS makes power factor and covers the 25 yards 0.068 seconds, which is noticeably faster than the projectile at 850 fps.

The purpose of this is give yourself an idea of where to hold on the target during the Mover. The rest is up to you as a shooter to have smooth follow through and clean trigger pulls!

2 thoughts on “Calculating lead on moving targets”

  1. Nit pick…not to be taken as criticism of the content of this post:

    Next to last paragraph:

    A 115 grain bullet at 1100 FPS makes power factor and covers the 25 yards 0.068 seconds, which is noticeably faster than the 850 grain projectile.[emphasis added]

    What is the nominal length of an 850 grain projectile for a 9mm, .38 or .38 super loading?

    Feel free to delete this comment after correcting the typo.

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