GroupScope: Measure Your Shot Groups on Any Target

Measuring a shot group by hand — callipers, ruler, squinting at overlapping holes — gives inconsistent results and takes time. GroupScope photographs your target and does the measurement automatically, giving you consistent, repeatable data across sessions.

What GroupScope Measures

• Extreme spread (ES) — the distance between the two most widely separated shots in a group, the standard measurement for group size
• Mean radius (MR) — the average distance from all shots to the group centre, a more robust metric when you have fliers
• Point of impact — where your group centre is relative to your aim point
• Shot count — automatically detected from the image
• Vertical and horizontal spread — separately, useful for diagnosing whether a consistency problem is mechanical or technique-related

How It Works

Photograph your target after shooting. GroupScope's detection algorithm locates the bullet holes, corrects for camera angle, and calculates the measurements. You can adjust the scale by entering the known dimensions of a target element (like a scoring ring diameter), which anchors the pixel-to-millimetre or pixel-to-inch conversion.

Session History

Every measurement is saved with the target photo, timestamp, and stats. Review your session history to see how groups change across a practice session — do they tighten as you warm up? Drift as you fatigue? Tracking this over time reveals patterns that single-session analysis misses.

Private and Offline

All processing happens on your device. Photos are stored locally. No account, no cloud upload, no subscription.

Download GroupScope from Google Play — free target measurement for Android.