Speargun power systems
Tackle · Last reviewed 2026-08-10
Band-powered and pneumatic guns store energy in completely different ways, and the difference decides maintenance, noise, recoil and where each one suits.
Safety
Entanglement — Can cause serious injury or death
A speargun is a projectile weapon. A loaded gun discharging accidentally — on a boat, at the surface, towards a buddy — causes catastrophic injury, and band failure under full load can injure the person loading it.
What reduces it: Load only in the water and unload before leaving it. Keep the muzzle pointed away from every person at all times, including when you believe the gun is unloaded. Use the safety and do not rely on it. Know where your buddy is before you point it anywhere. Replace perished rubber before it fails rather than after.
Shallow water blackout and breath-hold loss of consciousness — Can cause serious injury or death
A fish on the end of a spear is the commonest reason a diver extends a breath-hold beyond plan, and a more powerful gun means engaging larger fish that take longer to deal with.
What reduces it: Decide the limit on the surface and hold to it. If a shot fish needs more time than you have, let go of the gun — the float line is what recovers it. No fish is worth a blackout.
Precautions that always apply here
- Never spearfish or freedive alone.
- Dive one up, one down: one diver down, one on the surface actively watching, every single dive.
There are two ways to power a speargun, and choosing between them is the first equipment decision in the sport.
A BAND GUN stores energy in stretched rubber. It is mechanically simple, quiet, easy to maintain and easy to tune — adding or removing a band changes the power, and a diver can service the whole system with a knife and a length of rubber. Its limitation is that power scales with band length, so a powerful band gun is a long band gun, which is awkward in confined ground.
A PNEUMATIC GUN stores energy in compressed air inside the barrel. It delivers more power for a given length, which makes it far more manageable in caves, holes and confined rock. Its costs are maintenance — it is a sealed pressure system that needs servicing and can fail in ways rubber does not — and noise, since the discharge is louder and can empty a piece of ground.
A ROLLER gun is a band gun variant that routes the bands over a roller at the muzzle, gaining a longer power stroke without a longer gun. It is a genuine engineering improvement rather than a marketing one, at the cost of more parts to maintain and more to go wrong.
- Category
- Spearfishing equipment
What it does
Stores mechanical energy — in stretched rubber or in compressed air — and releases it through a trigger mechanism to accelerate a shaft over a short underwater distance. The power system determines the gun's length for a given power, its noise on discharge, its recoil, and how much maintenance it needs.
How to choose one
- Match gun length to the ground first: short in confined rock, caves and poor visibility; long in open reef and blue water.
- Band guns for simplicity, quietness and field-serviceability; pneumatics for power in a short package.
- More power is not automatically better — an overpowered gun in confined ground drives shafts into rock and is harder to handle.
- Whatever the system, the trigger mechanism and safety must be sound and understood before the gun goes in the water.
- Get instruction before buying rather than after. The right gun follows from the diving you will actually do.
What the numbers mean
BARREL LENGTH in centimetres is the headline figure and correlates with range and power for band guns. BANDS: diameter, number and stretch ratio determine power on a band gun; more bands means more power and a harder load. PNEUMATICS quote an internal diameter and a charging pressure. SHAFT DIAMETER in millimetres trades penetration against speed — thinner is faster and less durable. RECOIL rises with power and is what makes a very powerful short gun hard to aim. None of these figures means anything without the training to use the gun, which is the specification that actually matters.
Care, and how it fails
Band guns fail at the rubber and at the wishbones, both of which perish with ultraviolet light, salt and age, and both of which fail suddenly under full load — replace on a schedule rather than on inspection alone. Pneumatics fail at seals and valves and need periodic servicing; a pressure system that has been neglected can fail in ways a rubber band cannot. On any gun, inspect the line, the line attachment and the shaft before every session, and never store a gun loaded.
What each power system costs you, and what it interacts with
The three power systems are not better and worse. They trade different things, and each trade reaches other equipment.
BANDS are stored energy in stretched rubber. They are simple, field-repairable with nothing but a spare band, quiet, and forgiving of neglect right up until they perish. Power is added by adding bands, which lengthens the loading sequence and raises the effort of each shot — and loading is done in the water, on a breath, so a gun that takes three bands is a gun that costs breath before every shot.
PNEUMATICS store energy in compressed air. For the same power they are markedly shorter, which is why they are favoured in confined ground and in some Mediterranean traditions. The cost is maintenance: seals, lubrication and internal corrosion are real, a pneumatic cannot be fixed on a boat, and the charging system is one more thing to travel with. They are also noisier on discharge, which matters more than beginners expect on quarry that has been dived before.
ROLLERS AND INVERTED ROLLERS route the band around a pulley at the muzzle so that band stretch is longer than the gun. That gives more energy for a given overall length and a flatter power delivery — the shaft is accelerated over more of the barrel — at the cost of complexity, more parts to corrode, and a loading sequence that is unforgiving if it is done wrong.
WHAT THEY ALL SHARE. The energy has to end up in the shaft, and the shaft has to survive it. Every step up in power narrows the range of shafts that will not flex, and pushes the rigging towards a reel or a breakaway because a harder-hit fish runs harder.
AND WHAT NONE OF THEM CHANGES. Range in water is short whatever the system, because water decelerates a shaft very quickly. A more powerful gun buys penetration and a little reach, not a different kind of hunting — the approach is still the whole skill.
Authoritative guidance
Stated by a fisheries authority, scientific institute or recognised angling body. Authoritative, but summarising rather than demonstrating.
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Breath-hold spearfishing practice, equipment convention and the safety expectations set out by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
- BlueWater Hunting and Freediving — BlueWater Freedivers, Ventura, California, 1995 (Practitioner report)Relied on for: Spearfishing equipment and practice: gun and rigging choice, shot placement, and the handling of a shot fish, from a practitioner tradition distinct from the European one.States this directlyCitation checked — the work exists and is described correctly
- General angling website restatements of established technique — Various (Credible secondary source)Relied on for: Widely restated descriptions of equipment convention and rigging practice, recorded as consensus rather than as scholarship.Background and mechanism onlyCitation checked — the work exists and is described correctly
Where to go next
Where it is used
What these connections rest on (1)
Practitioner consensus — 1 connection
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
Spearfishing
A practitioner equipment claim about matching gun type to environment.
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: Equipment-handling discipline for in-water activities.Citation checked — the work exists and is described correctly
- General angling website restatements of established technique — Various (Credible secondary source)Relied on for: Widely restated practitioner guidance on speargun selection by environment.Citation checked — the work exists and is described correctly
What it works with
- Shafts and tipsThe gun accelerates the shaft; the tip decides whether the fish stays on. Tip choice is the more consequential of the two and gets far less attention.
- Speargun reelsA reel lets a fish run under drag and — the part that matters — lets the diver surface while still connected, which removes the commonest reason a breath-hold gets extended past sense.
- SpeargunsThe gun IS its power system in practice: bands, pneumatic or roller decide length for a given power, the loading sequence, the maintenance burden and how much noise the shot makes.
What these connections rest on (3)
Practitioner consensus — 2 connections
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
Shafts and tips
An equipment relationship with a welfare consequence, stated at practitioner level.
- General angling website restatements of established technique — Various (Credible secondary source)Relied on for: Widely restated practitioner guidance on matching tip type to target fish size.Citation checked — the work exists and is described correctly
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: Equipment inspection and maintenance practice.Citation checked — the work exists and is described correctly
Spearguns
A dependency between equipment, recorded because choosing one of these constrains the other. Convention, recorded as convention.
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Breath-hold spearfishing practice, equipment convention and the safety expectations set out by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
- BlueWater Hunting and Freediving — BlueWater Freedivers, Ventura, California, 1995 (Practitioner report)Relied on for: Spearfishing equipment and practice: gun, shaft, tip and rigging choice, and the handling of a shot fish, from a practitioner tradition distinct from the European one.States this directlyCitation checked — the work exists and is described correctly
Authoritative guidance — 1 connection
Stated by a fisheries authority, scientific institute or recognised angling body. Authoritative, but summarising rather than demonstrating.
Speargun reels
An equipment claim whose justification is a safety mechanism rather than a fishing advantage, which is why it is not labelled as practitioner preference.
- DAN guidance on freediving safety, hypoxia and shallow-water blackout — Divers Alert Network (Water-safety or diver-training authority)Relied on for: That extending a breath-hold to deal with a fish is a principal contributor to hypoxic blackout.States this directlyPassage read and verified
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: Entanglement as a recognised hazard and the equipment practice addressing it.FishingHQ's interpretation of what it saysCitation checked — the work exists and is described correctly
Understanding it
- Pneumatic spearguns, and what they tradeWhat compressed air buys and costs: markedly shorter for the same power, and a maintenance and travel burden a band gun does not have.
- Roller and inverted-roller speargunsThe third power system in detail — band stretch routed around a muzzle pulley so that stretch exceeds gun length, buying energy for a given size at the cost of complexity.
What these connections rest on (2)
Practitioner consensus — 2 connections
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
Pneumatic spearguns, and what they trade
An explainer carrying a mechanism the equipment record depends on.
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Breath-hold spearfishing practice, equipment convention and the safety expectations set out by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
- BlueWater Hunting and Freediving — BlueWater Freedivers, Ventura, California, 1995 (Practitioner report)Relied on for: Spearfishing equipment and practice: gun, shaft, tip and rigging choice, and the handling of a shot fish, from a practitioner tradition distinct from the European one.States this directlyCitation checked — the work exists and is described correctly
Roller and inverted-roller spearguns
An explainer carrying a mechanism the equipment record depends on.
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Breath-hold spearfishing practice, equipment convention and the safety expectations set out by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
- BlueWater Hunting and Freediving — BlueWater Freedivers, Ventura, California, 1995 (Practitioner report)Relied on for: Spearfishing equipment and practice: gun, shaft, tip and rigging choice, and the handling of a shot fish, from a practitioner tradition distinct from the European one.States this directlyCitation checked — the work exists and is described correctly
Instead of this
- Bands and wishbonesThe rubber is the engine and the wishbone is the smallest component carrying the entire load. Both are consumables that fail suddenly, at full stretch, with a hand in the load path.
- Pole spears and Hawaiian slingsThe two ends of the same activity. A gun buys range and mechanism; a pole spear removes both and makes the approach the entire skill, which is why it is simultaneously the sensible first purchase and a deliberate choice by experienced divers.
What these connections rest on (2)
Authoritative guidance — 1 connection
Stated by a fisheries authority, scientific institute or recognised angling body. Authoritative, but summarising rather than demonstrating.
Bands and wishbones
An equipment claim with a direct injury mechanism, held above practitioner level because the failure happens during loading rather than during fishing.
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: Equipment inspection and handling discipline for in-water activities, and the principle that consumable components are replaced on a schedule rather than on inspection.FishingHQ's interpretation of what it saysCitation checked — the work exists and is described correctly
Practitioner consensus — 2 connections
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
Bands and wishbones
A dependency between equipment, recorded because choosing one of these constrains the other. Convention, recorded as convention.
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Breath-hold spearfishing practice, equipment convention and the safety expectations set out by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
- BlueWater Hunting and Freediving — BlueWater Freedivers, Ventura, California, 1995 (Practitioner report)Relied on for: Spearfishing equipment and practice: gun, shaft, tip and rigging choice, and the handling of a shot fish, from a practitioner tradition distinct from the European one.States this directlyCitation checked — the work exists and is described correctly
The two power systems are the standing comparison in the discipline.
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: Diving body guidance on equipment types.Background and mechanism onlyCitation checked — the work exists and is described correctly
- Sea Angler — Bauer Media (Specialist angling publication)Relied on for: Equipment practice in spearfishing.States this directlyCitation checked — the work exists and is described correctly
Pole spears and Hawaiian slings
A comparison a diver is genuinely choosing between, joining two records that resolve one another.
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Breath-hold spearfishing practice, equipment convention and the safety expectations set out by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
- BlueWater Hunting and Freediving — BlueWater Freedivers, Ventura, California, 1995 (Practitioner report)Relied on for: Spearfishing equipment and practice: gun, shaft, tip and rigging choice, and the handling of a shot fish, from a practitioner tradition distinct from the European one.States this directlyCitation checked — the work exists and is described correctly
Check the rules before you fish
Fishing laws, bylaws, access rules, seasons, bait restrictions and permitted methods vary by location and can change. Check the current rules from the relevant authority and the water you intend to fish before fishing.
Check with:
- Current national or regional law for where you are fishing
- Current local bylaws
- The relevant fisheries authority
- The landowner, club or fishery whose water it is
- Any restrictions specific to the species or the method you intend to use
Sources for this page
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: Equipment-handling discipline and buddy practice for breath-hold diving activities.FishingHQ's interpretation of what it saysCitation checked — the work exists and is described correctly
- DAN guidance on freediving safety, hypoxia and shallow-water blackout — Divers Alert Network (Water-safety or diver-training authority)Relied on for: That extending a breath-hold beyond plan is a principal contributor to blackout.States this directlyPassage read and verified
How FishingHQ labels evidence is explained in the evidence policy.