Comparisons
What the compare answers compute: the spread of each figure across the compared records, and the head-to-head's winner per figure, with the direction it treats as better stated as the choice it is.
The spread of a figure
The compare answers put records side by side and, for each figure, return the lowest value, the highest, and the spread between them as a share of the lowest.
A figure is compared only when at least two records state it; otherwise its spread is empty. The spread is empty too when the lowest value is zero. It is a spread, not a verdict: nothing here says which record is better.
Firearms are compared on empty weight, loaded weight, barrel length, overall length, magazine capacity, effective range, muzzle velocity, muzzle energy, rate of fire.
Cartridges are compared on bullet diameter, neck diameter, shoulder diameter, base diameter, rim diameter, case length, overall length, bullet length, maximum pressure in MPa, maximum pressure in psi, typical bullet weight, typical muzzle velocity, typical muzzle energy.
Head-to-head verdicts
The head-to-head answer compares two firearms and names a winner for each figure. Which way counts as better is an editorial choice, not a measurement: lighter and shorter win because most readers comparing two guns are choosing one to carry, and a longer barrel wins because it is what buys velocity. Read the verdicts against your own use, and reverse any that does not suit it.
| Figure | Counts as better |
|---|---|
| empty weight | Lower (lighter) |
| overall length | Lower (shorter) |
| barrel length | Higher (longer) |
| magazine capacity | Higher (higher) |
| muzzle velocity | Higher (faster) |
| muzzle energy | Higher (more powerful) |
| effective range | Higher (longer) |
| rate of fire | Higher (faster) |
A verdict needs both figures. Where only one record states a figure the answer names no winner and says unknown: a figure nobody recorded is a gap in the catalogue, not a loss. Equal figures are a draw, and a figure neither states is left out.
Worked example: Glock 17 Gen5 against Glock 19 Gen5
The Glock 17 Gen5 against the Glock 19 Gen5, from their records. The spreads and the winners are the endpoints' own functions, run as the page loads.
| Figure | Glock 17 Gen5 | Glock 19 Gen5 | Spread | Head-to-head |
|---|---|---|---|---|
| empty weight | 625 | 610 | 2.46% | Glock 19 Gen5 |
| loaded weight | 863 | 855 | 0.94% | - |
| barrel length | 114 | 102 | 11.76% | Glock 17 Gen5 |
| overall length | 202 | 185 | 9.19% | Glock 19 Gen5 |
| magazine capacity | 17 | 15 | 13.33% | Glock 17 Gen5 |
| effective range | 50 | 50 | 0% | Draw |
| muzzle velocity | 375 | 360 | 4.17% | Glock 17 Gen5 |
| muzzle energy | 519 | 481 | 7.9% | Glock 17 Gen5 |
| rate of fire | - | - | - | Unknown |
Neither record states a rate of fire, so it has no spread and no winner. Loaded weight has a spread but no head-to-head verdict: the head-to-head does not compare it.