Research › Range tests
The range test log
GroupLab project, tested by Alan Hayes, researched and written with Claude. Written 2026-09-22; the data is from Running log; latest entry 2026-09-23.
This article is a draft. It is not finished, it is not linked from the research index, and anything in it may change.
Print tests, September 2026
Question: does a GroupLab sheet print at its true size, and can GroupLab detect when it does not?
What was done: test sheets printed at 100 percent and deliberately at 96.2 percent, scanned at 300 and 600 dpi.
What we learned: Alan's printer at "Actual size" measured 1.0001 horizontally and 1.0006 vertically. GroupLab measured the reduced sheet at 0.96200 (600 dpi) and 0.96201 (300 dpi).
Written up in: "Does your printer print at true size?", "Scanner traps".
First range sheet
Question: does a real, shot sheet read the way generated test sheets do?
What was done: nine shots on a 25-bull letter sheet, scanned flat.
What we learned: this first real sheet started the work on how GroupLab reads holes in real paper, rather than in simulated targets.
Range day, 2026-09-20
Question: how does GroupLab do across calibres, with shots that land between bulls, with a blank zero sheet, and with phone photos against scans of the same sheets?
What was done: five 25-bull load development sheets (GL-CF25-LTR-D), one blank zero sheet and one commercial target, all at 100 yards. Every sheet was scanned at 600 dpi and photographed with a phone in several bursts through the afternoon, 59 photos in all. A second phone photographed the 6mm Creedmoor sheet.
| Sheet | Cartridge | Load as written | Shots | What it tests |
|---|---|---|---|---|
| 1 | 6.5 Creedmoor, 28 in Seekins | 153.5 gr LRHT, 42.4 gr H4350, Alpha brass, 7.5 BR primer, 2.874 in | 15 | One shot per bull, rows 1 to 3 |
| 2 | 6.5 Creedmoor | Zero group | A blank sheet with a hand-drawn cross | |
| 3 | 6.5 Creedmoor | Same as sheet 1 | 25 | A full sheet; now GroupLab's sample scan |
| 4 | .22 LR, 20 in CZ | SK Standard Plus, 40 gr | 23 | Strong crosswind, windage changed after row 2 |
| 5 | 6 ARC, 18 in RTR | 108 gr ELD-M, 27 gr N140, Starline brass, GM205MAR, 2.250 in | 20 | A load the rifle was not zeroed for: shots land nearer the wrong bull |
| 6 | 6mm Creedmoor, AI AXSR | 120 gr LRHT, 39.0 gr N550, Lapua brass, 2.810 in | 10 | Five shots with GM205MAR primers, five with CCI BR-4 |
What we learned:
- GroupLab's counts matched the shooter's on every scanned load sheet, after two detection defects found on these sheets were fixed.
- Assigning each hole to its nearest bull gives confident but wrong groups when shots land between bulls (sheets 4 and 5). GroupLab now lets you say which bulls you aimed at.
- Switching primers on sheet 6 moved the point of impact clearly, while the difference in spread could not be shown from five shots each.
- Photos place a sheet almost as precisely as scans, but hole sizes in photos depend on the light.
- The original bull was hard to see through lower magnification and less expensive glass.
Written up in: "Why a photo cannot tell you your bullet's size", "A bullet hole is not the bullet", "Did the primer matter?", "When shots land on the wrong bull", "Scans against phone photos", "Wind or rifle?", "Zeroing on a blank sheet", "Pooling groups", "How to photograph a target", "Scanner traps", "Can you see the bull?".
Aim point test, 2026-09-23
Question: which aim point designs can shooters see and centre on at 100 yards, across scopes of different magnification and glass?
What was done: a card of nine designs at 100 yards, scored through a Vortex Razor HD Gen III 6-36x56, a DNT TheOne 7-35x56, a Vortex Strike Eagle 5-25x56 and a Primary Arms PLxC 1-8x24, plus a friend's scope, by two observers.
What we learned: [Placeholder: summary of the 2026-09-23 results.]
Written up in: "Can you see the bull?", "Aim points for 1x to high power optics".
Next
- Aim point tests for 1x red dots and prisms, low power and medium power variables, at distances suited to each.
- More sheets per load, so loads can be compared with enough shots to mean something (see "How many shots do you need?").
Data
data/range-day-2026-09-20.csv: the six range-day sheets, cartridges, loads as written, shots and notes.