Mares Sten Pneumatic Speargun for Scuba Divers

Mares Sten Pneumatic Speargun: A Compact, High-Performance Pneumatic for Serious Spearo

The Mares Sten Pneumatic Speargun is a pneumatic speargun, meaning it uses compressed air stored inside the barrel to drive the shaft, rather than rubber bands like a band-powered gun. If you already know your way around pneumatics and want a compact, maneuverable gun that punches hard for its size, the Sten is worth a serious look.

This is not a beginner's first purchase. It suits an experienced spearfisher who understands how to charge and maintain a pneumatic, and who wants a gun that handles well in tight reef structures or when tracking fast, mid-sized fish.

What Makes the Sten Different

The Sten runs a 13mm inner barrel inside a 40mm outer barrel. That inner diameter is on the larger side for a pneumatic, and it matters: a wider bore allows the gun to accommodate both 7mm and 8mm threaded shafts, giving you flexibility depending on what you are hunting.

The 8mm shaft included with the gun is a solid choice for medium to larger reef fish. When you want a lighter, faster setup, you can swap to a 7mm rod without changing the gun itself.

The muzzle is described as a lightweight, one-piece design. Combined with the compact head, this keeps the front end of the gun from feeling nose-heavy when you are tracking a fish. That balance matters more than it sounds when you are holding aim for several seconds.

Hydrodynamics and Handling

Pneumatic spearguns live or die by how well they move through the water. The Sten's reinforced ogive (the tapered front section) and compact head are shaped to reduce drag as you swing the gun onto a target.

The aluminum construction keeps the overall weight down. Aluminum also resists corrosion in saltwater, which matters for a gun that will spend a lot of time in the sea and needs to be rinsed and stored repeatedly over a long season.

The ergonomic handle uses a white grip. The white color is a practical choice underwater: it stands out in low-visibility conditions and makes the gun easier to track visually when you are repositioning.

The Trigger and Shaft System

The Sten uses a reinforced spinner with a steel line guide. This is the component that holds your shooting line in place along the barrel and guides it cleanly on release. A steel guide here is more durable than a plastic one and less likely to snag the line mid-shot.

The 1.5mm connection piston links the shaft to the internal pressure system. This is a standard pneumatic component; if you ever need to service the gun, knowing this spec helps when sourcing replacement parts.

A manual injector is included. You use this to charge the gun with air before diving. If you have not used a pneumatic before, this is the tool that pressurizes the barrel, and having it in the box means you are ready to go without sourcing accessories separately.

What the Sten Is and Is Not Built For

This gun is designed for mid-range spearfishing on reef and coastal species. The compact, hydrodynamic build makes it particularly well suited to situations where you need to maneuver quickly, around rocks, through kelp, or in current.

If you are hunting large pelagic fish in open water, where a longer, more powerful band gun typically dominates, the Sten is probably not your primary weapon. It is a precision tool for the diver who values accuracy and handling over raw range.

If you are new to pneumatics entirely, be aware that pneumatic spearguns require more maintenance than band guns. Seals need periodic inspection, and the gun must be properly depressurized and rinsed after every dive. The Sten is built to last, but only if you treat it accordingly.

Quick Specs at a Glance

The Mares Sten rewards the spearfisher who already understands pneumatics and wants a well-engineered, compact gun that handles precisely in the water. If that describes you, it is a strong choice.