Medium Cobra 105

Medium Cobra 105 – With Professional Trigger System and Stainless Steel Accessories

Designed as a versatile speargun, the Medium Cobra 105 is suitable for all skill levels, from beginners to advanced spearfishers. Its body features integrated band lifters that align the rubber bands parallel to the shaft, eliminating their natural downward tilt. This unique design, coupled with its streamlined shape, ensures exceptional maneuverability and ease of tracking underwater. The head’s silhouette, resembling a cobra, gives the gun its name.

Conventional Propulsion System & Performance

Personally, I used a similar handmade version (the Cobra is its evolution) equipped with two Sigal Extreme 17.5 mm bands and was highly impressed by its shooting power and accuracy. The special design ensures the bands sit neatly side by side, without overlapping, preserving a clear line of sight. It handles extremely well and reduces vibrations during lateral and vertical movement. Vertical reels are recommended to reduce bulk. The gun accommodates an 8 mm shaft. Turned Delrin bushings are required at the band holes in the muzzle (see photos), protecting the wood during loading, as Dyneema lines can cause damage.

3D Model for Speargun and Handle

Designed for milling on exotic hardwoods like teak, iroko, and mahogany. The package includes .STEP and .STL files for all accessories, compatible with 3D printing and CNC machining on plastic materials such as Delrin.

Included DXF Projects

The package contains the complete professional trigger system with quick-release "cam" brackets in DXF format, ideal for laser cutting on stainless steel. Other included DXF files:

• Lead weight compartment covers
• Muzzle accessories
• Handle plates
• Butt plates

All files come with detailed technical drawings in PDF format, including step-by-step folding and machining instructions.

DXF files allow accessory production via stainless steel laser cutting or CNC milling on carbon fiber s—ideal for flat structures without bends.

Speargun Manufacturing

This model is optimized for engraving on hardwoods. Use 3- or 4-flute milling bits specifically designed for wood. Using improper tools may compromise cut quality.

With an 85 cm shaft travel, the gun is suitable for all spearfishing techniques, including ambush and hole fishing.

Trigger System – Precision & Safety

Engineered with micron-level tolerances, the trigger mechanism offers maximum safety and reliability. Laser cutting must be performed by qualified technicians to prevent misfires or malfunctions.

The trigger housing bending requires high precision—any misalignment may compromise its function.

Recommended materials for internal components:

• AISI 316 (excluding 316L)
• AISI 316Ti
• AISI 420
• AISI 440C
• AISI 630

Use of AISI 304 (18/10 or 18/8) is strongly discouraged due to its low hardness and poor mechanical and wear resistance.

Stress test: The trigger system successfully withstood a static load of 280 kg for 48 consecutive hours without failure.

Wood Preparation

The structure of the gun does not require any special considerations for its construction.
Due to its size, it can be made from a single-species laminated block without alternating soft or lightweight woods.
Always use hardwoods like iroko, teak, or mahogany for the strips, bonded with D4-class polyurethane adhesives.

Reduction System & Performance

The reduction system boosts power, range, and accuracy by increasing shaft travel and acceleration.
The Vela inverter system virtually eliminates recoil, delivering an extremely stable shot trajectory.

Recommended configurations:

• 2 pairs of medium-diameter bands (15–17 mm)
• or 3 pairs of small-diameter bands (14 mm)

Bands run underneath the barrel, while the Dyneema shooting line stays on top, enhancing handling and tracking speed.

Handle Finishing

After milling, the speargun is ready for assembly.
Only one manual operation is required: sanding and shaping the grip saddle (highlighted in pink in the images), which is left rough to allow anatomical customization.

Three handle sizes available: small, medium, and large.

The handle can also be made from Delrin or glass-filled nylon. In this case:

• Avoid using epoxy resins
• Use D4-class polyurethane adhesives
• Sand surfaces before bonding

Key Dimensions:

• Muzzle height: 34 mm
• Muzzle width: 55 mm
• Maximum body width: 78 mm
• Maximum body height: 40 mm

Included Files (STEP, STL, and DXF formats):

• Speargun body
• Handle (3 sizes)
• Handle plate
• Butt plate
• Threaded lead inserts
• Lead compartment covers
• Professional trigger system
• Cam brackets
• Muzzle line anchor

Included Technical Drawings (PDF):

• Trigger system
• Muzzle accessories

Technical Note:
Specifications and parameters for laser cutting and CNC milling depend on the type of machine and the operator’s preferences.
Standardized settings cannot be provided without knowing the equipment used.