Colonial Marine Conversions #2: Smart Gun


Another Aliens-themed item is the smart gun, which can be made easily from a couple of heavy weapon bits and a set of flamer arms. This conversion also requires one bit left over from the Sentry Gun conversion.

Incidentally, the original version of this weapon used an Imperial Guard vehicle heavy stubber, but that part makes for an expensive conversion, so I went back to the drawing board to find a way to get the same sort of weapon from cheaper and more common bits.

Anatomy of a Smart Gun

The basic idea behind the smart gun is that it’s a large and somewhat cumbersome machine gun that automatically tracks targets by means of sensors and an actuated harness system, while the actual firing is done by the operator. The significant characteristics of this weapon are, therefore, its size, the auto-tracking capability, a high rate of fire, and the fact that it’s fed by a drum magazine. We are going to incorporate those themes so that while the converted smart gun does not look exactly like the one in the movie, it will still have the correct look and feel.

Required Parts

The photo below illustrates the parts needed for this conversion. 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 smart gun.


  1. Shave off the details on the right side of the flamer, making sure the surface is as flat as possible. (The eagle, rivets, and tubing)
  2. Slice the flamer up so that only the parts highlighted in red remain.
  3. Glue the flamer grip section upside down to the front of the flamer.
  4. Shave the back of the flamer muzzle so that it is completely flat.
  5. Glue the flamer muzzle upside down to the front of the flamer.
  6. Slice up the bipod so that only the parts highlighted in red remain.
  7. The smartgun barrel is formed by the bipod leg–slice off the bipod foot and the leg swivel, and the barrel is the leftover section.
  8. Shave the front and back of the barrel as flat as possible, then glue it to the front of the flamer muzzle.
  9. Clean up the leg swivel so that there are no remaining traces of the leg that you sliced off in Step 6. Glue that to the bottom of the flamer, directly in front of the handgrip. This adds more visual weight to the back of the smart gun, and suggests a waldo attachment point.
  10. Glue the bipod cradle to the right side of the flamer.
  11. Glue the heavy weapon targeter to the “knob” on the bipod cradle.
  12. Slice out the ribbed autocannon barrel segment. This will be the ammunition drum–make sure the front and back are nice and flat, then glue it to the lower right side of the flamer where it meets the bipod cradle. There is a peg on the bipod cradle that will serve as a convenient guide that fits between the 2 ribs on the drum.
  13. When you glue the smart gun arms into place, consult the photo below as to where the left hand should be positioned.

You’re done! Repeat this one more time, and you’ll have a pair of smart guns.

Important note: One heavy weapon bipod yields two smart gun barrels and two waldo attachment points. So, if you do both smart gunners, you’ll actually be using one and a half bipods, not two whole bipods. Use both legs and the bipod cradle of the first bipod, then remove only the bipod cradle from the second bipod. This way, you’ll have two intact bipod leg assemblies to use in the upcoming autoloading mortar conversion.

In the next article, we’re going to make a couple of flame units.

16 thoughts on “Colonial Marine Conversions #2: Smart Gun

  1. Joseph

    I like the way this one worked out…
    If you keep this up,I will spend much too much time thinking about ways to improve GW Imperial troops…

  2. Mel Ebbles

    You say that like it’s a bad thing. 😀

    Plastics are fun and cheap, and I enjoy getting my Frankenstein on with them. I do wish, however, that there were more companies with a range of science fiction themed plastic kits comparable to or better than what Games Workshop offers.

  3. Joseph

    Similar to the Sentry gun this little darlin looks BAAADD!!!
    I had contemplated adding a plasticard tube piece between the gunners torso armour and the gun to add to the “realism” of the piece as the Colonial Marines have a articulated armature to assist in the controlled gun movement (see the pre-deployment part in the movie where Vasquez and Drake dance around a bit with their smart guns) but after looking at the left over space I had to modify that idea.
    This was agreat idea and thanks for sharing it.

  4. Mel Ebbles

    Glad you like it! I was going to try and figure out how to do the waldo linkage too, but there just wasn’t enough room between the weapon and the gunner’s body. So I just added a joint to the bottom of the smartgun (the thing in front of the grip) and called it a day.

    I still like the older vehicle stubber based version of this conversion because it actually has the vertical side grip and is more recognizable as a smartgun.

    It’s a shame IG don’t normally carry heavy stubbers, as it would be really cool if there were a 100% legal way to use the smartgun conversion in 40K.

  5. Joe

    Comments on a tuesday
    As an FYI:
    There are two parts provided that look like the classical twin handgrips (anyone familiar with a .50 cal will know what I mean)in the Heavy weapons set, if you cut these in half and glue one of these handles with a bit of plastic on to the weapon in a suitable place,i.e. just above the ammo drum then you have a side mounted charging handle.
    To the next idea of the support frame which connects the smart gun to the body gear.
    If you use the hose attachment which was cut off from the flame thrower arm, first cut off the attachment valve evenly from the end of the hose and glue this part with the sloped part of the valve onto the belt of the troopers body. Then trim the remaining hose to the right length to fit between the valve that you glued onto the belt and the upside down flamer grip section that is in the middle of the smart gun(just below the hand of the flamer arm (L))fill any gaps in with green putty and prime that baby for battle with the paintbrush!!

  6. Joe

    Hi Mel,
    I found the following on a GW site:
    Platoon 189 HQ Junior Officer with Bolt Pistol. 41
    Platoon 189 Squad 1 9 Guardsmen, 1 Sergeant; 1 Grenade Launcher, 1 Autocannon.

    As far as I rememner the Autocannon is the Heavy Stubber known and loved from the Necromunda game.

  7. Mel Ebbles

    Nope. The autocannon is a Str 7 heavy weapon mounted on a tripod, and that list entry is basically allowing a normal squad to take a 2-man heavy weapon detachment. Ideally, the smartgun would be used as a heavy stubber for a proper sense of proportion.

    I’m not worried about it that much anyway, as I don’t play 40k much anymore, and I can use these figures in 5150 or Guncrawl without having to bend the rules. 🙂

  8. rustynail456

    I wish they had Heavy stubbers too or some sort of SAW…but….
    why not use it as a heavy bolter….?

  9. Mel Ebbles

    ‘Cause the sentry gun counts as a heavy bolter, and it’s way bigger than the smart gun. I’d have trouble justifying that to myself from a common sense standpoint, so it’s better off being labeled as a heavy stubber. I don’t play in tournaments, and I don’t usually play points-based games at home anyway, so I’ll just house-rule it for the rare occasion that I use the 40K rules.


  10. Anonymous

    I don’t play tournaments either, just my son and I. I would justify it as having an advanced targeting system and a higher rate of fire that keeps more shots on the target therefore increasing its strength.
    The old RT rules stated that strength had many things factored into it including rate of fire…lol just food for thought. 8)


  11. Foss1066

    Mel- I just came on to your blog site; your conversions are very clean, extremely well presented, and down right inspiring! The largest reason I play 40k is for the cool conversion possiblilites. Thanks for the awesomeness and cool tricks

  12. Colorcrayons

    This is a great smart gun conversion. I am so glad I found your site as I have been laboring for some time on how to effectively recreate one and you have the best answer to this problem I have yet seen.

    If you dont mind, I would like to steal your idea for my ongoing Aliens themed space hulk project and link to this site for reference and credit purposes.

  13. Mel Ebbles

    Feel free to do so. The whole point of sharing my conversions in that detailed fashion is so others can make use of them too. 🙂


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