GunSpec

Similar firearms

How the similar firearms answer is ranked: a weighted sum of what two guns share, each trait with a band for its whole weight and one for half, worked through on two real records.

Two guns are scored on what they share. Each trait carries a weight; a measured trait earns its whole weight when the candidate's figure is close to the target's, half when it is further off, and nothing beyond that. The weights add to 1.00.

TraitWeightWhole weight whenHalf when
Same category0.25Always, since only guns of the target's category are scored-
Shared calibers0.20Two or more sharedOne shared
Same action0.15The same-
Empty weight0.10≤ 20%≤ 50%
Barrel length0.10≤ 15%≤ 40%
Year introduced0.10Within 10 yearsWithin 30 years
Magazine capacity0.05≤ 25%≤ 60%
Same maker0.05The same-

A percentage band is the difference over the target's own figure, so a 600 g pistol is close to a 700 g one and a 6 kg rifle close to a 6.9 kg one. The bands are GunSpec's choice, set so that a variant of the same gun scores near the top and a gun of the same kind from another maker a little below it.

Only guns in the target's own category are scored, which is why the category earns its 0.25 on every row. Up to 100 of them are scored, chosen by the traits the score weighs most: guns sharing a caliber first, then the same maker, the same action and the nearest year. The answer lists the ten highest scores.

A trait either gun does not state earns nothing: it is neither assumed to match nor counted against the candidate. Two sparse records therefore score lower than two full ones that agree, which ranks the better-known guns first. Ties keep the candidates' order above, then their ids.

The Glock 17 Gen5 and the Glock 19 Gen5, from their records. Both are pistols, both fire 9x19mm, both are short recoil and both are Glock's.

TraitComparedEarns
Same categoryBoth pistols0.25
Shared calibers9x19mm, one shared0.10
Same actionShort recoil, both0.15
Empty weight625 g, 610 g (2%)0.10
Barrel length114 mm, 102 mm (11%)0.10
Year introduced2017, 20170.10
Magazine capacity17, 15 (12%)0.05
Same makerGlock, both0.05
Score0.90

Every trait earns its whole weight: the weights differ by 2%, the barrels by 11% (inside 15%), the capacities by 12% (inside 25%). The score is computed by the endpoint's own function as the page loads.