Airsoft 40mm Howitzer/Artillery 'MAS-40mm' Modular Pull-Activated Cannon System

The first of its kind, a mortar/Howitzer hybrid. We introduce the MAS-40mm. This custom artillery device shoots BBs, clouds of powder, or really any and every projectile that fits through the barrel. Powered by popular and widely available 40mm airsoft gas shells (MOSCART/shower shell and TAGINN shells are compatible), the cannon is powerful enough to shoot projectiles over 100 meters (varies depending on the shell and gas). The mechanism features a pull-cord/lanyard to fire, resembling modern 155mm/105mm Howitzers used today (M777, M101, etc.). The hatch at the breech provides quick and realistic reloads, as well as a secure holding spot for the shell.

• Powered by reusable and popular 40mm airsoft gas shells (compatible with TAGINN and most types)

• Realistic lanyard-operation (pull-cord) and hatch system

• Capable of firing BBs, powder, and projectiles (dummy rounds, 3D-printed projectiles, chalk rounds, etc.)

• Non-pyro and safe to use for any event or regular game-day

The MAS-40mm also features a realistic muzzle-brake, sling mounts, a rifled chamber, and the option of ambidextrous controls (you can choose for the lanyard to be pulled from the right or the left side, using the exact same hardware).

Watch the overview video here: https://youtu.be/Q0u1qmHxx7o

Hardware needed:

PVC pipe sections (for the barrel, lower body, and legs). You only need two diameters: 1-1/2 inch and 1 inch. For the larger pipe, we recommend a 3-foot length for the lower body and a 1.5 foot length for the barrel (you can make the barrel as long as you want). For the legs (the 1" pipe) we recommend about 3.5 feet each. You can easily cut these sections with a hacksaw, PVC cutter, or any regular wood saw. ABS pipe can also work, but the dimensions and tolerances might be a bit off.

1x Standard AEG spring. M95 strength seems to work best. You'll need to cut a 12mm section from the end, which will act as the return spring in the sear mechanism. You don't want it to be too strong, otherwise it will take too much force to pull the lanyard.

2x M4x150mm threaded rod. One of these will be for the handle bars, and the other to stabilize the mechanism/spring guide.

12x M4x12mm bolts. All connecting pieces use these bolts to retain consistency of hardware. A pack of 50 or 100 of these bolts runs very cheap on Amazon, eBay, or even hardware stores.

1x M5x20mm grub screw. This will act as the striker, which hits the bottom of the 40mm shell. You could also use a regular M5x15mm bolt with a small head diameter if you're unable to find grub screws, but we wouldn't recommend it.

4x M4x30mm bolts. These are for the legs/bipod and Frame connection.

OPTIONAL: 2x Cotter pins (with keychain rings). We've made a 3-position locking system for the legs, allowing you to lock them at 45 degrees. They will automatically lock out at 90 degrees (without pins), but if you want a locked 45 angle, the pins allow for this. Dimensions are 1/8 inch x 1-1/4 inch for the pin. They are not absolutely necessary.

Some string. Synthetic nylon thread works great. If you want some more realism, you can attach a thick rope to the string for a bigger lanyard. 6ft is standard for most artillery, but you can use as much as you like.

Any sort of strong tape, to hold the muzzle brake (which is optional). Glue is also recommended for the parts that are press-fit if they are too loose, although not required.

Assembly Guide:

The full assembly guide is attached as a PDF document in the files due to its length and detail.

To load use the MAS-40mm: Reset the mechanism by pulling the handle bars down all the way until it clicks, which automatically catches it. Open the hatch to reveal the chamber, and insert a loaded 40mm gas shell inside. You can optionally load in a large projectile before the 40mm shell (right on top of it). While holding the shell, close the hatch. Unravel the lanyard (if wrapped) and the howitzer is ready to fire. Simply pull the lanyard with a little bit a force and the mechanism will go off (it doesn't take much force to activate, so don't pull too hard).

In terms of shells: Any standard 40mm airsoft gas shell will work (shower shell, TAGINN, multi-purpose, etc.). You can load them with BB's, projectiles, or even powder to create a massive "smoke-cloud" effect (flour, ash, chalk, cornstarch, etc.). The barrel can also be directly loaded with large projectiles along with a shell. You can even load the howitzer with a projectile-less shell (meaning only gas) and drop in a large projectile through the muzzle, just like a mortar. Although, keep in mind that the PVC pipe barrel is usually just a tiny bit smaller than most standard 40mm shells (only about 1mm at most), so make sure that whichever projectile you're using fits through the barrel before firing.

Don't leave the mechanism cocked. We are not responsible for any misuse of this design.

We do not permit unauthorized resale of digital files or physical prints of this design.

PLA+ works well for all the parts. We recommend using a rigid material, as the frame is prone to bend a little with more flexible materials like PETG. Most parts are printed in 0.2mm layer height. Although, you could use any layer height (we wouldn't recommend anything bigger than 0.24mm)

Lower Frame: Print upright. 3-4 walls. 30-50% infill. No supports needed.

Upper Frame (Shell Breech): Print upright. 3 walls. 30-35% infill. Use supports only for flat overhangs.

Striker: Print upside-down (with spring-guide up). 3-4 walls. 40% infill. Use supports for flat overhangs (inside the catch cut-outs).

Hatch: Print upright. 4 walls. 40-60% infill. No supports needed.

Handle Bars: Print on the flat face (holes facing down). 3 walls. 20-30% infill. No supports needed.

Sear: Print upright (as oriented). 4 walls. 99% infill (or completely solid with walls). Use supports on the flat overhangs.

Sear Cap: Print upside-down. 3 walls. 20% infill. No supports needed.

Baseplate: Print upside-down (spike facing up). 3 walls. 20-40% infill. No supports.

Leg Connectors: Print on the flat surface. 4 walls. 50-70% infill. No supports.

Leg Spikes: Print upright. 3 walls. 25% infill. Use supports for flat overhangs.

Muzzle Brake (Optional): Print upside-down. 3 walls. 20% infill. No supports.