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M392 Bandit Build Guide

Updated: Jun 18, 2023


The M392 is a fantastic project with features such as standard picatinny rails on the top, sides an bottom of the rifle. Additionally, the rifle features a movable trigger, receiver slide, removable magazine and toggleable fire selector.

The magazine is magnetic and fits 7.62mm rounds.

For a full write up of all the features you can find them listed on the main product page.


This Build Guide will list the following:

  • Require materials to complete the project

  • Assembly videos to walk you through the assembly process

  • Recommendations for Print Settings/Orientations for certain pieces

Any additional questions you have concerning the building of this rifle can be sent directly to me via the contact page on my website



Build Requirements



Non-Required Hardware

M3 Bolts (To secure any rail attachments including the foregrip, top sight, and DMR scope)

M2 Bolts (To secure the front sight and flashlight mounting ring)



Assembly Instructions

The M392 Bandit is comprised of 3 main subassemblies.

The Barrel Subassembly

The Front Body Subassembly

The Rear Body Subassembly

The videos below will show how to assemble each and finally how to assemble them into the finished Bandit Rifle


Barrel Subassembly

In order to assemble the Barrel Subassembly, take the following steps

  • Insert the Top Barrel Rear and Bottom Barrel Rear through the Rear Bracket into the Mid Bracket.

  • Insert a Barrel Screw Connector through each Barrel and the Mid Bracket to secure everything together

  • Screw the Top Barrel 2 and Bottom Barrel 2 onto the Barrel Screw Connectors from the previous step in order to attach these pieces to the Mid Bracket.

  • At this point you can also attach the Top Barrel Strut 1 and Top Barrel Strut 2 to each other, place within the mid bracket and attach to the Rear Bracket

  • Attach the Front Bracket to the Top Barrel 2, Bottom Barrel 2, and Top Barrel Strut. You can secure it in place with two more Barrel Screw Connectors

  • Place Top Barrel 1 and Bottom Barrel 1 on the exposed Barrel Screw Connectors from the previous step to secure them to the Front Bracket

  • ** Be aware that the first layer of any print will likely be a bit wider as it is flattened against the build plate. There are settings to avoid "Elephant Foot" and ensure that this doesn't stop Barrel Screws from inserting into barrels, or barrels from inserting into brackets. Additionally, you can also just hit the base of these prints with a little wet sand paper before attempting assembly.


Front Body Subassembly

In order to assemble the Front Body, take the following steps

  • Insert the Rear Sight LED Dial, both Rear Sight Dials, and the Rear Sight Buttons, into the Rear Sight

  • Slide the Rear Sight onto the railing of the Barrel Housing & Railing from the rear. This can be secured with an M3 bolt if desired

  • Insert the Front Knob into the front of the Barrel Housing & Railing

  • Slide the Underbarrel Railing over the front of the Barrel Housing & Railing from the front

  • Slide the Foregrip onto the Underbarrel Railing from the front. This can be secured with an M3 bolt if desired

  • Place the Body Panel Top, Side Rail, and Body Panel Bottom in place and secure with a Master Screw or a Master Peg. A total of 12 Master Screws or Master Pegs will be required to secure both sides.

  • Place all Cosmetic Screw in their designated spots. x3 for the Rear Sight, x1 For the Barrel Housing & Railing, x2-4 for the Foregrip (this depends on whether or not you used M3 Bolts)


Rear Body Subassembly

In order to assemble the Rear Body, take the following steps

  • Insert the LED Screen into the Rear Body

  • Insert the Slide into the Rear Body. The rubber band should already be hooked into the rear Body when this is done, to ensure that the rubber band is able to be fed all the way through the slide cavity. Tie a string to your rubber band and feed the string through the Rear Body from the rear to the front. Pull this string to pull the rubber band/slide through the Rear Body to the front.

  • Hook the rubber band around the Slide Hook and insert the Slide Hook through the front of the Rear Body. At this point you can remove your string. The rubber band should be pulling your slide to the front most position in the Bandit Rifle

  • Place the Trigger, Trigger Hook and one of you magnet sleeves into the Grip. The magnetic sleeve should have the magnet side facing the rear to put less distance between the magnets in the Grip magnet sleeve and the Magazine magnet sleeve. I like to just insert the magnets and place a strip of scotch tape over the face to keep them in place. You can also utilize glue.

  • Hook a second rubber band around the top of the Trigger and Trigger Hook. At this point you should be able to test to ensure you have the desired Trigger tension.

  • Place the Rear Body into the Grip from the top

  • Secure the Rear Body to the Grip with the Rear Body & Grip Locking Pin

  • Insert the Fire Selector, Positive Dial, and Negative Dial into the Grip

  • Insert the Slide Handle into the Slide

  • Place the Cheek Pad and both Rear Body Top Brackets onto the Rear Body from the Top. The Rear Body Top Brackets will require glue in order to secure to the Rifle.

  • Insert the Ejection Port into the Cheek Pad and Rear Body from the Right of the Rifle. This will Secure the Cheek Pad in place. If it is desired to remove the Ejection port, and can be poked out from the inside of the rifle by going through the rear slide entrance

  • Slide the Magazine Cradle over the Grip from the Rear

  • Secure the Magazine Cradle to the Grip with the Magazine Cradle Locking Pin

  • Secure your Magazine Cradle Top Panels with a Master Screw. This will require x2 Master Screws

  • Place the Ejection Button, Cosmetic Screws, and Master Screws in their respective locations on the rear of the Grip and the Magazine Cradle. This will require x2 Master Screws, and x4 Cosmetic Screws for Both Sides. The Ejection Button is not function and will require glue to secure. The magazine is secured by internal magnets

  • Insert the second Magnet Sleeve into the Magazine with the magnet face facing the front of the Magazine. This will reduce the distance between the magnets in this Magnet Sleeve and the one in the Grip.

  • Place the Stock Pad onto the rear of the Grip and Rear Body and secure with the Stock Pad Upper Pin and Stock Pad Lower Pin


Full Rifle Assembly

Once all the Subassemblies are built according to the instructions above, you are ready to assemble your completed M392 Bandit Rifle!

  • First: Slide the Barrel Subassembly into the Front Body Subassembly from the rear-side of the rifle. At this point you can also add any rail attachments you want to the Front Body Subassembly. Included in this file set are the in-game fore grip and rear-sight.

  • Second: Attach the Sight Bracket and all pieces forward of it, to the end of the Barrel Subassembly. This will include the Front Sight, Front Sight Prop Arm, Flashlight, Flashlight Ring Mount, Top Barrel Tip, Flash Hider, Bottom Barrel Tip, and x2 Barrel Screw Connectors

  • Third: Slide the Rear Body Subassembly onto the rear of the Barrel Subassembly. At this point the Front and Rear Body Subassemblies should be touching.

  • Lastly: Slide the Barrel Locking Pin up through the Rear Body Subassembly and Barrel Subassembly. Place the Hand Guard into the Grip and secure with x2 Master Screws or Master Pegs. This will lock the two halves of the rifle together. Once that is complete you can attach the handguard to complete your new Bandit Rifle!


DMR Scope

After popular demand, the original DMR scope from Reach was added as a compatible attachment. It is also compatible with any Picatinny Rail


  • Insert the Rear Lense into the Rear Scope and insert into the Body from the Rear

  • Insert the Forward Lense into the Rear Scope and insert into the Body from the Front

  • Insert the Top Dial into the Body from the Top

  • Slide the DMR Scope onto the Top Sight and insert an M3 bolt to secure it to the Top rail


General Printing Tips

For this rifle, most of my tips will follow along three main themes: Optimal print orientations for the strength of load-bearing pieces, printing tall towers and optimal print orientations for reducing the amount of supports.


For slicing software, I recommend Ultimaker Cura. It is the slicing software and therefore the one I am most familiar with. Additionally, it features many helpful free plug-ins such as "Custom Cylindrical Supports", that allow one to add custom supports to pieces with complex geometry. This plug-in will be extremely helpful for some of the pieces I will be showing in this guide.



Print Orientations for load-bearing pieces:

There are a number of locking pins used in this rifle that are used to keep pieces in places. These pieces will undergo bending stresses and therefore should be printed with their layers aligning with their longitudinal axes. The following pieces should be printed in the following orientation to maximize their strength and minimize their chance of snapping

Stock Pad Upper Pin

Stock Pad Lower Pin

Barrel Locking Pin

Top Barrel Rear

Bottom Barrel Rear

Magazine Cradle Locking Pin

Rear Body & Grip Locking Pin

Trigger Hook


Printing Tall Towers

There are several large pieces that are most ideally printed in a vertical orientation. This is to ensure that large faces with that piece are kept relatively smooth so that they can slide freely over other large pieces on the rifle. If these pieces were printed horizontally, it would require many supports and the support face would be rough and likely effect the tolerances of the print itself.

These pieces are the Rear Body and Foregrip however the principles here can be applied to other pieces as you feel necessary


I recommend printing the Rear Body vertically as this will ensure the internal cavity for the Slide is smooth and allow for the easy movement within the Rifle. As with any tower, ensure you are printing with properly leveled build plate for proper bed adhesion, utilize a brim of 6-8 mm to improve bed adhesion, and utilize a clean/heated bed. You can clean it with rubbing alcohol. As you can see the main focus is build plate adhesion when printing tall towers.

After all that is in place we will use the previously mentioned "Custom Cylindrical Supports" plug-in on Ultimaker Cura to place custom supports to allow for a much more stable print. Feel free to utilize the settings and placements that I show in the screenshot below. I place a large support along the spine right below the opening to the LED Screen. I also place one on the bottom of the Rear Body right below the locking pin openings as I dont want the support face to mess with the locking pin tolerances. The tolerances are generous so don't feel the need to totally avoid this area, but support removal can be annoying if it is totally covered. Lastly I added two supports on either side. As you can see this will vastly increase the ratio of base surface area to tower height and increase the chance that you have successful print.


Lastly I will mention that due to the extreme length of this piece and the fact that the Grip it fits into are recommend to be printed in different orientation. Your X,Y and Z print calibration steps need to be calibrated to ensure they still fit into each other easily. When I printed the rear body the first time I found out that due to a .5% error in my Z step calibration, there was a 1.5mm error in the Rear Body Length. Once I calibrated my printer based on that info, I reprinted the Rear Body and it fit like a glove


The Foregrip is easier to print and can utilize the same methods above to ensure that it can be printed vertically to maintain a smooth inner surface to slide over the top of the bottom picatinny rails of the rifle


Print Orientations for minimal support use:

Most of my models are designed to be printed with minimal supports. They do have to be reoriented to achieve this so for the most part look for large flat faces but I will point out some specific pieces in this section.

  • Under Barrel Railing

Placing the model on its front face will minimize the overall need for supports and allow it to easily slide over the Barrel Housing & Railing

  • Barrel Housing & Railing


Printing the Barrel Housing & Railing on its rails will ensure there are no required supports on the inside of the piece. You can also use the "Custom Cylindrical Supports" Plug-in to block any supports that would generate on the circular overhangs. This includes all screw holes and the diagonal slot holes. In my experience supports in these circular overhangs are unnecessary and can be annoying to remove

  • Grip

In order to fit the Grip on your build plate, place it at a 45 degree angle and set it on its flat top face. This will ensure the magazine slot is smooth. There will be large internal supports so ensure your print settings are set to all for easy removal of supports on 90 degree overhangs.

  • Magazine Cradle

This piece has a couple different methods you can print it in but the way I printed it is in this orientation. You will have to turn off snap rotation and use the lay flat button to help you align these faces with the build plate. If this doesn't work, printing in the default orientation is the second best.

  • Rear Sight

Printing the Rear Sight on its Rear Face will have the least supports and ensure the female picatinny slot maintains good tolerances

  • Slide

Printing the Slide on its right diagonal face will minimize support use and make for a stronger print orientation for the load bearing rubber band hook in the front




Final Results:

When all is said and done you should have something that looks like this!






Feel free to email me pictures of your builds @josephaguilarsanchez97@gmail.com and I'll showcase them here!


I hope you found this build guide helpful, if you have any questions at all feel free to contact me using the contact page on my website



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