Colonial Marine Conversions #1: Sentry Gun


The first conversion we’re going to start with is the sentry gun, because we’ll need some of the leftover bits for later conversions.

Anatomy of a Sentry Gun

In order for a weapon system to convey its autonomous nature, it needs to look the part. So, the sentry gun conversion has 3 major components: the weapon itself, the transceiver module, and the sensor module. The transceiver module is essentially just a box with an antenna on it, and it suggests to the casual observer that the thing is remotely operated. The sensor module contains the imaging, targeting, and fire control systems, and further builds upon the autonomous impression given by the transceiver module. To make it look somewhat portable, there are two carrying handles on top of the sentry gun.

Required Parts

The photo below illustrates the parts needed for this conversion, nearly all of which come from the heavy weapon squad box. When only a small portion of a part is required, the important piece is highlighted in red. (Save the leftover pieces! They’ll come in handy later.)


The photos below show how all the parts listed above go together to assemble a sentry gun.

Component 1: Weapon Body

  1. Lascannon: Slice the lascannon barrel and rail off completely, so that only the lascannon body segment highlighted in red remains. Shave the left side of the lascannon segment flat (just the rivets and a couple of details on the “armor” section)
  2. Heavy Bolter: Slice off everything behind the feed/ejection ports, so that only the heavy bolter segment highlighted in red remains.
  3. Test fit the heavy bolter and lascannon pieces. You may need to bevel the bottom rail on the bottom rear of the heavy bolter to a 45 degree angle to ensure a flush fit. If the test fit looks good, glue them together. Fill any gaps with Squadron putty if needed.
  4. Slice the muzzle brake from the autocannon’s barrel. Glue it to the heavy bolter’s barrel.
  5. Carefully cut the drum off the grenade launcher arm. Do this by first removing the barrel, then by slicing off everything behind the drum. Make sure you don’t damage the grip section or the hand–you will need the arm later!
  6. Shave down the top of the drum so that it is flat. Test fit the drum to the feed port on the right side of the heavy bolter segment. It should fit in snugly–if not, shave the front and rear of the drum a little more until it seats nicely into the feed port. Once the fit is just right, glue the drum into place.

Component 2: Transceiver Module

  1. Cut the bottom half and the antenna off the voxcaster backpack.
  2. Test fit the voxcaster bottom half to the right rear side of the weapon. You will need to shave off 2 button-like details from the lascannon segment to ensure a good fit.
  3. Once satisfied with the fit, glue the voxcaster bottom half to the right side of the lascannon segment.
  4. Glue the antenna to the top rear of the voxcaster half to finish off the transceiver module.

Component 3: Sensor Module

  1. Glue the lascannon power pack to the left side of the lascannon segment. The power pack is large enough to cover the entire left side of the armor “cowl”, with a slight overhang to the rear.
  2. Cut the binoculars into front and rear halves at the spot where they taper from the middle.
  3. Glue the front binocular half to the lascannon power pack to finish off the sensor module.

Finishing Touches

  1. Glue the tripod to the bottom of the sentry gun assembly.
  2. Cut the carrying handle off the autocannon drum half. Do this carefully so you can ensure a nice level fit in the next step without shortening it too much.
  3. Make sure the flat pieces at the front and back of the handle are level. If not, shave or file down the longer of the two flat pieces until the handle will sit level on a flat surface.
  4. Glue the carrying handle to the top right side of the sentry gun, across from and lined up with the other carrying handle attached to the sensor module.
  5. Glue the sentry gun to a 40mm base.

You’re done! Repeat this 2 more times, and you’ll have a full set of 3 sentry guns.

In the next article, we’ll build some smart guns.

3 thoughts on “Colonial Marine Conversions #1: Sentry Gun

  1. Joseph

    Well after reading your tutorial and building a smart gun, I will have to admit to liking the way it looks.
    The best comment came from my 13 year old son though “Cool… but that looks like it could hurt my Orks…”
    Stifled grin here…

  2. Mel Ebbles

    Smart gun or sentry gun? That’s a cute comment from your son either way 🙂

    Incidentally, I haven’t had a chance to finish the rifleman and squad leader articles on account of having to temporarily pack up all of my hobby stuff. (I needed the extra workspace for a work project), but I’m hoping to finish them before the end of the month.

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