Pneumatic speargun

A pneumatic gun stores energy as compressed air in the barrel. Loading pushes the shaft in against the air; the trigger releases a piston that drives it out. The barrel doubles as the power source, so a short pneumatic hits harder than a band gun of the same length, and there are no bands to age, tangle or snap.

Its natural home is close-range work: holes, caves, thick weed, the murky surge, where a 50 to 70 cm gun that shoots hard is worth more than a long one that cannot be swung. It was the standard gun of Mediterranean spearfishing for decades and still is for many divers who hunt rock.

Pneumatics reward divers who maintain their gear and punish those who do not. The seals, the piston and the barrel are a system, and a leak means a gun that loses power through the session.

What matters:

• Length: 50 to 70 cm for holes and surge, 70 to 90 cm as an all-rounder. Beyond a metre a pneumatic becomes hard to load and loses the advantage.
• Power regulator: a switch that halves the pressure for close work and loading; worth having on any gun you will load repeatedly in a session.
• Loading effort: at full pressure a pneumatic is hard to load; a loading pad on the suit is not optional.
• Noise and recoil: pneumatics are louder than band guns underwater and kick more; a gun with a vacuum barrel is quieter and more accurate, and costs more.
• Shaft: pneumatic shafts are specific to the gun, 7 or 8 mm, and thread into a piston; spares are a brand matter.
• Serviceability: seals and oil should be easy to get where you live. Ask before you buy.

A pneumatic is not a beginner's gun. The loading is hard, the maintenance is real, and a leaking gun on a Moroccan beach with no spares is a paperweight.

50 to 70 cm for hole work, 70 to 90 cm as an all-rounder. Pressure is set with a hand pump; the manufacturer's figure is a maximum, not a target, and most divers run below it.

Rinse the outside, never open the barrel wet. Oil the piston as the manufacturer says, replace the seals every year or two, and keep the muzzle plug and the loading tool with the gun. A pneumatic that loses pressure overnight has a seal problem; fix it before the next dive.