How To Choose Right Speargun Trigger Mechanism

When the trip of a lifetime is underway, the last thing you want is gear that you can’t trust. Trigger mechanisms are one of the most involved parts of a speargun that we never think about, affecting accuracy, safety, and ease of use. The features of various trigger mechanisms should be well understood to make the right choice for a personal use speargun.

Understanding Speargun Trigger Mechanisms

The idea behind a speargun trigger mechanism is to hold the shaft via a notch in its back end, then let it off cleanly and fluidly when you shoot. They have to be able to hold up against as many pounds of force as the bands exert on them, so they have to be built sturdily and leave no room for slippage. There are different types of trigger mechanisms, and a person can choose one depending on the styles of spearfishing they practice and the environment in which they are in.

Considerations in Selecting a Mech for Speargun

These are the most important factors to consider when selecting the proper speargun trigger mechanism:

• Durability: The trigger mechanism should be made of good stainless steel for marine-grade specification because spearguns are submerged in saltwater during use and, in many cases, subject to the worst environmental conditions. In addition, the mech needs to be strong enough to hold fast under extreme pressure from the bands.
• Smooth Trigger Pull: This is accompanied by ergonomics. Triggers that automatically fit the shooter's finger keep shooting effortless which grants greater accuracy when firing.
• Compatibility with Shaft Sizes and Styles: Always check whether the trigger is compatible with the size of your shaft and the style. Most shafts come in either “Euro” or “American” style, which have differences in the notch at the back of the shaft that clicks into the trigger mech. 
• Line Release System: Automatic line releases by some triggers make reloading easier and more convenient.
• Ease of Installation: Neptonics carries trigger installation hardware that takes the guesswork out of putting a trigger in your gun build.

Varieties of Mechs

Different types of triggering mechanisms cater to different spearfishing needs. Below are some of the most popular Neptonics trigger mechanisms, which have corresponding installation hardware:

Reverse Trigger Mech

The reverse trigger mechanism is used in both bluewater and reef scenarios because it allows for extra band stretch, because the spear shaft is locked at the back of the mechanism. Traditional mechanisms load at the front, which means the length of the mechanism on the gun itself isn’t contributing to band stretch. Loading at the back of the mech allows for the absolute maximum stretch of the bands, giving you more power and range in shooting.

Specs:

• Allows extra band stretch for more shooting power.

• Automatic line release and straightforward to use.

• Compatible with American-style square-notch spear shafts.

• Rectangular profile for easy traditional install (chisels and drill press)

Tuna Speargun Trigger Mech

The tuna mech is most commonly used for bluewater hunting since it is explicitly designed for high-strength applications and is meant to resist heavy loads targeting world record pelagics.

Specs:

• Endurance for forces beyond 1,400 lbs.

• Accommodates up to 6 power bands with ease.

• Works with various shaft sizes (9/32, 5/16, 11/32, and 3/8 inches)

• Compatible with American-style square-notch spear shafts.

• Fully rounded ends for easier router install

Double Trigger Mech

A double-trigger mechanism is a boon for divers wishing to fire two shots quickly. This mechanism saves a diver the trouble of reloading immediately, which is one of the reasons why it is highly effective in various hunting scenarios. Many scuba divers prefer this style of mechanism, but it’s rare to see in freediving because freedivers tend to only have the breath hold to effectively hunt and return to the surface with one fish.

Specs:

• Allows two swift consecutive shots.

• Constructed with 100% marine-grade stainless steel for durability.

• Compatible with American-style square-notch spear shafts.

• Comes with an installation package including mounting hardware and pushrod.

Reef Speargun Trigger Mech

This mechanism has been tested extensively, is preferred by many members of the Neptonics team, and is the most proven for the smaller spearguns used on the reef.

Specs:

• Smooth release that increases shot accuracy.

• Compatible with American-style square-notch spear shafts.

Why Quality Matters in a Speargun Trigger

When the design of the trigger mechanism is not up to snuff, it may cause a misfire, accidental discharge, or trigger mechanism failure which can put a gun out of use for a whole trip. Because mechs are exposed to saltwater constantly, a quality mechanism should be expected to be made from stainless steel and have as few small individual parts as possible (small individual parts tend to rust quicker). A speargun mech isn’t a clock: more complicated doesn’t mean better. Detail should be paid to the spring and internal parts of the mechanism, but more parts than absolutely necessary means more opportunities for failure, which is why neptonics mechs are machined out of single pieces of stainless steel, to limit screws and connection points on the mech.

Installation Tips:

• Use a unique installation jig to take the guesswork out of installation and align all the parts correctly. Neptonics carries jigs tailored to each of our mechs, which are important because once you drill a hole for a pin, if it’s in the wrong place you can’t regrow the wood (you can do the old sawdust and superglue trick, but it’s still not the same).

• Securely pin retaining pins within the speargun frame to avoid any movement.

• If at first it doesn’t fit, be very slow, deliberate, and gentle with chiseling or sanding out excess material until the trigger fits snugly.

Maintenance Tips:

• Flush through your mech after every dive with fresh water to remove excess salt and debris from the mechanism. Point the water flow INTO the mech so that you’re able to get all the internal parts, not just outside the mech. 

• Make regular inspection checks for wear, rust, and corrosion on the trigger.

• Lightly coat all moving parts with marine-grade lubricant or oil to ensure the smooth functioning of the moving mechanism.

• Store the speargun in a dry, cool spot to minimize moisture exposure when on land.

We hope this article helped you consider the differences between different trigger mechs, and if you have any questions for the shop feel free to email jeff@neptonics.com!