DIY project - Make your own (replica)
RPG-7 Grenade Launcher

for about £7


 

A while ago, I watched Peter 'Lord of the Rings' Jackson's first film, Bad Taste. I wont explain the storyline, but as the good guys are killing the aliens, one of the weapons used is a grenade launcher. When I saw it, I had a sudden urge to make one - not for destructive purposes, but just for display.

I did a bit of research and I found that the one used in the film was an RPG-7 (Rocket-Propelled Grenade, model 7)*. It was a popular weapon for the Iraqies in the Gulf War (both of them), and it's been used in plenty of films (including Back to the Future, Rambo, Terminator) and computer games (Metal Gear Solid, Call of Duty, etc). If, like me, you have too much spare time, check here for a more complete list.

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After a bit of thought, I went to Instructables.com to see if there were any tutorials on making one. There were loads!

However, I already had my own ideas on how I'd do it, and none of the tutorials seemed practical for me. I wanted to make it on a very small budget, using things I already had or were easy to find. I can't see the point in splashing out lots of money for an idea that could fail. I always start small and see how things go.

I'll put my shopping list at the end.

 

Rocket

This, of course, was the first part I tackled. If I couldn't make a decent rocket, there'd really be no point in the project.

Attempt 1:

Initially I tried to make just the visible part of the rocket.

I decided that I'd be able to make this from the top of two bottles, stuck together. I tried this with 500ml Coke bottles.

I joined the bottles with sellotape, but this wasn't very rigid (1a). I put a vitamin bottle between them, and this was considerably better (1b).

I wedged a bottle cap into the top of the barrel, so I'd be able to screw the end of the rocket directly into it.

The picture on the right is an early one, taken when I was still experimenting with ideas. It shows the first 'rocket' screwed into the barrel. Although it was fully screwed in place, it was still a bit wobbly.

It didn't look very good, so I spent a few days wondering how to make this look better.

Attempt 2:

One lunchtime on my daily scour of Poundland, I spotted a Skittles game made from toy traffic cones. I knew these would make a much better rocket!

I trimmed the square base from 2 of the cones and used them to make a bigger, more solid rocket. I decided that I might as well build a full version of the rocket (i.e. with a shaft), rather than just the visible part. This would give me a more secure way of attaching it to the barrel. I cut the top from one of the cones so I'd be able to slide it along a shaft.

At this stage, I was frequently thinking about how I'd be able to make this work, so my though-process was a little scattered. Some of the descriptions and pictures are out of order, but it will all make sense at the end.

I found a 21" length of 3/4" tube in my dad's garage and decided that this was the right kind of size for the shaft. I put the uncut cone on top of it, and pushed the other piece along the tube to meet with it. This would be so much easier to explain with a diagram...

These pictures show cross-sections of the rocket parts. It's a lot easier to visualise like this, rather than me putting several fully-assembled photos in and then trying to explain what went where.

I put the plugs in to keep the tube central through the cones.

One of my testing-strip bottles (see Notes) is just narrower than the RPG Barrel, with a ridge on it that's just wider. It would be perfect for making an end for the rocket, enabling the shaft to fit down the barrel but stopping at the ridge behind the grenade. It also provided a smooth, paralled place to put the fins. I cut the bottom off the bottle (injury-free this time) and used a hacksaw to run 4 grooves (equally spaced) around it. I cut 4 fins from an ice-cream lid and superglued them in place.

I cut open two more pieces of the pipe used for the rocket shaft, and clipped them over the existing shaft behind the fin section. I pushed them up to create a segmented taper along the shaft (sorry, no specific pictures for this, but you can just about see the change in thickness in the one below).

I superglued the screw thread of a bottle to the end of the shaft, so it could be attached (screwed in) to the Barrel. This is explained further on.

I used black electrical tape around the join between the cones to prevent any movement. I used superglue on the shaft to make sure bits weren't sliding around, and primed the whole thing.

Once primed, I painted most of it in green fence paint (it needed several coats to eliminate the streakyness) and sprayed the bottom section in chrome.

At some time later in the project, I was bored, so I made a similar shaft for the original bottle-rocket. It still looked a bit crap. I might put a picture in at the end, along with a few other out-takes.

 

Barrel

The barrel was made in several sections - the barrel itself, the trigger, the ignition chamber and the heat shield. I've dealt with the heat shield in a seperate section because it was more complicated.

Barrel: I had bought 5' of 1.5" black tubing for this part. After a bit of juggling numbers and deciding on a scale, I cut the tubing down to 30". Fortunately, as I had 5ft of tubing, this was exactly in half, so I'd have a spare barrel should I make a mistake with the first one.


Ignition Chamber*
: I used a tall (Highball) cocktail glass for the wider metal part of the barrel. It was made of plastic, so technically it was a Cocktail Plastic.

I carved out the botton of the 'glass' so it could be pushed along the tube.

I used a cereal box to make a roll of card around the tube and I kept adding layers to this until it matched the diameter of the cocktail glass. This kept it straight along the barrel. The widest end of his was positioned exactly half-way along the barrel (green line).

*This section may not actually be called the 'Ignition Chamber', but it's about level with where the end of the Rocket goes (and indeed, ignites), so I thought the name would do.

Trigger: For this I found a large toy pistol in a charity shop. I cut off the top part of the gun's barrel, and trimmed the remaining plastic so it could be fitted to the barrel of the RPG. I attached the butt of the pistol against the narrow end of the cocktail glass.

I temporarily held it in place with a cable-tie, so I'd be able to experiment with the distances and lengths of the other barrel parts still to add.



Support Handle: This was just a small block of scrap wood (1/4" x 3 1/4" x 1 1/4"). I cut pieces of an ice cream lid and stapled them halfway along the wood. I curved the top of each so they could be attached (superglued) around the ignition chamber.

It was probably a bit thin, but it stayed in place, didn't wobble around and it looked pretty good when the whole thing was together. This was made pretty late-on in the project. I'd tried various different ideas, but this was the simplest end easiest.

 

Barrel Peripherals: Iron Sights & Carrying Strap

Sights: These were each made from a 2" length of wood and a shelf bracket. I gave the wood some curvature so it could be attached to the Barrel easily, and drilled a hole to fit the bracket plug. As with everything else, they were both primed and painted black. One was glued onto the very end of the Barrel, and the other onto the Ignition Chamber, just before the Heat Shield.

Due to a slight miscalculation, I cut one of these in half so I could fit the Optical Sight around it. When I saw different pictures of the RPG, I realised the the Optical Sight goes beside the fixed sight, rather than over it.

 


Strap: This was made from a dog lead & collar from Poundland. It involved a little reconstruction of the lead, attaching the collar to increase the length and repositioning of the plastic slide to give it an adjustable length. I attached a lobster clip (from keyrings) to each end of the strap and cable-tied metal loops to the ends of the barrel.

 

Breech

As with the Rocket, I had 2 attempts at this, the second being considerably better than the first.

Attempt 1 - Initially, I'd bought a cup-style ashtray to use as the Breech. I attached the top half of a Coke bottle to this so I'd be able to screw it into the barrel. It didn't look good at all, so I gave it another shot...

Attempt 2 - This was made from one of the traffic cones I'd bought for the rocket. It hadn't occured to me to use one of these in the first place. I bolted a bottle cap to the top and trimmed the square base down to a circle. I was very pleased with this one.

I put it aside ready to be primed and sprayed black.

Job done. Easy-peasy.

 

Pretty early on in this project, I had an idea how to use bottle cap screw mechanism to attach the Rocket into the Barrel. The testing-strip bottles I use (see Notes) are only fractionally narrower than the tube, so (after trimming off the ridge) I bolted a bottle cap to one (for the Rocket) and attached the screw thread to another (for the Breech). I wrapped a little duct tape around each, so they could be wedged in the Barrel. They're relatively easy to remove should alterations need to be made.

These pictures show how my testing-strip containers were also suitable for the rocket fin-section.

 

 

Progress so far...

This picture was taken at some stage along the development, but I forget when.

 

Wooden Heat Shield

This bit was a nightmare. I messed around with this bit so often and so unfruitfully so many times, it ended up being the very last piece I finished.

The heat shield needed to cover the rear half of the 30" barrel, so it had to be 15" in length.

I spent a long time working out where the diameter would change, how much it should change and the angle at which it should change. I knew it had to meet up with the top of the cocktail glass, so that gave me a diameter for the large section (just over 2"). Eventually I gave up and took approximate lengths from one of the pictures I had. I should have done that in the first place.

The part of my brain that could do trigonometry vanished a while ago. This obviously caused problems trying to work out the distances and angles that would procuce a smooth transition from the wider diameter to the narrower one over a specified distance. With the help of the internet, I figured it out (eventually).

I could spend a lot of time here describing how I cut these sections, but I think I'll just put a picture. I cut out these shapes out of the wood-design stickyback plastic and mounted them on sections cut from of a 2 litre lemonade bottle (with built-in curvature - you try cutting one of those bottles open and trying to make it lay flat!).

I had to bulk out the of diameter of 8" of barrel to match up with the cocktail glass. I did this with cardboard from cereal boxes.

The grain all had to be in the same direction, along the length of the barrel, which meant I needed the curvature to be across the grain, rather than with it (of course, the roll I had bought went the wrong way). The bottle-section would have helped with this, but first I had to stick the stickyback to the bottle sections, with the natural curvature at 90 degrees to each other. This involved rolling out the required length of fabric, flattening it (took several days) and then rolling it back up along the other dimension (again, took several days for the new curvature to 'set').

Finally, it looked like this (except it was real, not a diagram).

 

Black Bits

All bits primed and painted. Those 2 bits in the middle were not necessary - I'd painted them with the rest as I'd thought they could be used to make the support handle.

 

Optical Sight

Fairly early on in this project, as an extra, I decided to make an Optical Sight, which is often used with this weapon. I looked on the internet to get a better idea on what i was aiming for. Unfortunately, I did misjudge the position of this (explained in the Peripherals section earlier)

The next day, I found this interesting-looking water pistol. With a little bit of imagination, I decided how I could make this work. The bottom half of a real Sight is only used to attatch it to the barrel, so I ignored that and dealt mainly with the business-half.

I cut off the grip and trigger, and trimmed down the blue water chamber on top. I superglued the screw-thread part of a bottle to each end.

In an extremely fiddly procedure, producing a horrible mess of twisted cable ties, I managed to attach a Terry clip to the base.

I expect one of the cable ties will snap if the clip is moved too vigourously, so i'll have to re-do the section with a nut and long bolt.

I probably should have done it like that in the first place, but I didn't have a long bolt whereas I had oodles of cable ties.

To make the thing look more solid, I cut a few pieces from and ice cream tub and superglued them over the gaps. Injury 1 occured when I pushed down in the wrong place and had to cut a section of plastic from my finger with a stanley knife. Injury 2 occued when I was trying to tidy up a rough section of plastic near the Terry clip. I sliced a thick flap of skin into the knuckle of my thumb. Superglue to the rescue!

Please note that although superglue was invented during the second world war as a quick fix for wounds, it's current composition is apparently NOT SAFE to use for this anymore. However, I did not know this, and I still have all my fingers.

After a little sanding and tidying up, it was ready to prime and then paint green (same green as the rocket). This needed several coats.

I used a black bottle cap as a lens cover. As the end of the sight was made from a bottle neck, it screwed on and off perfectly. It was attached to the body with a shoelace. I glued part of an insulin pen to the side of the body as another dial.

I wrapped black tape around the eyepiece section, and ta-da!

With a little bit of imagination and artistic licence, it's not too far off. There are loads of variations of Optical Sights used, so this will do.




Several weeks after making this, I decided I needed to rebuild it. I had already discovered that I was trying to put it in the wrong place, so I wanted to try again. I had no idea how I was going to build a detatchable Sight parallel to the iron sight.

My childhood came to the rescue - I was always a fan of Lego, and I thought I'd be able to make a more accurate one from that. My old Lego set has since been passed to my nephew, but I was sure he wouldn't miss a few bits.

I cut the cable ties attaching the Terry clip (99p wasted!) and trimmed down the plastic a little more to leave a relatively flat base to the sight. I supergued a 2x8 plate of Lego to this. That gave me somewhere to start.

I superglued a 1x4 bar upside down to the side of the Ignition Chamber. If I built the rest of the stand from Lego, and superglued it to the sight, I'd be able use this barrel section to clip on the rest (2 rows of 4 knobs on different levels).

Again, this would be so much better explained with a few pictures. I remember what the Lego Assembly instructions looked like, and I have an uncontrollabe desire to create my own manual. Here goes....

 

This is not an official Lego design, but it was extremely easy to make the stand from it. It is structually sound, allowing the Optical Sight to be attached or removed as required.


1) The mount. This was attached (upside down) to the side of the Ignition Chamber. All these bits were superglued together.
2) The bottom-half of the stand. Again, all superglued.

3) Top-half. Ditto superglue.

The little yellow bit on the end was used to attach the string holding the lens-cap.

4) The halves were pushed together (and superglue applied)...
5) ...to make this...

I had built it from whatever colour Lego I could find, but for these instructions I used bright colours from the Photoshop pallete to make it easier to follow.


6) Both sections were finished, and they needed painting.

Fortunately, I all bits I needed to be black were made from black Lego so didnt need painting. If I'd made the instructions in black, visually they would have been a blob.

The middle section had to be painted with the same green as the rocket.


7) The stand for the Optic Sight was effectively built upside down, as this is the way it needed to work.

The mount was attached to the side of the Ignition Chamber, and the stand itself was superglued to the bottom of the Sight.

8) It was easy to assemble and dissasemble, so the Sight could be removed or attached on a whim (or willy-nilly, whichever term you prefer).

All the superglue used made sure the wrong bits didn't come apart.


These are pictures of my completed sight and a real sight. Not a million miles off. Bearing in mind that mine was built from a water pistol and lego, I can live with the differences.

 

Variations

Overall, there are many versions of the RPG weapon. I have aimed to create an RPG-7, but I have been working with the objects easily available to me, so the dimensions do not exactly match up. For example. the rocket I've built is oversized compared to a real one, but I think this accentuates it - after all, it is the business-end of the weapon. Without the rocket, the RPG is just a big tube with handles.

Also, the real RPG is of a larger scale. I made this one to fit me, and I'm only 5'8". The real one weighs over 7kg, but mine is less than 1kg. I know I've used an imperial scale for most of this, so it's about 2lbs. My version is still over 4ft long (just over 50")

However, there is no mistaking which weapon this is supposed to be. I am happy with the result. It is hanging on the wall in my study, along with the coke-bottle rocket.

 

Notes

1) An Internet search for "rpg weapons" yielded very little except magical swords and troll axes. Not the right sort of RPG.

2) I am lucky enough to be diabetic, so I have access to a myriad of interesting items, a number of which were used in this project. I built the fin section of the Rocket from a testing-strip bottle, the black nut on the Sight is from the end of an insulin pen and I used another few testing-strip containers to wedge the screw mechanisms (for the Rocket and Breech) into the Barrel. Nothing goes to waste when project-building!

3) RPG could understandably stand for "Rocket-Propelled Grenade", but actually stands for Ruchnoy Protivotankoviy Granatomyot, meaning 'Hand-held Anti-tank Grenade Launcher" in Russian. I can't figure out why the RPG-7 is a 7.

 

Warning

Considering the current political climate, with terrorist attacks happening all over the world, I would not advise carrying the thing around or keeping it in plain view. It has replaced the Kill Bill Samauri sword on top of my cupboard, in plain view to my friends and visitors, but not visible from outside.

Although I've been painting various bits on my balcony, I've only done it one part at a time. I expect that if I'd been waving the whole thing around, looking threating (as if!) or pointing it at cars in the road, I'd have been visited by armed police by now (and I haven't - only the normal police, for a completely different reason).

Having said that, there has been a full-sized skeleton sitting on my balcony since last October, and no-one has said a word.

 

My point about realism...

A long time ago (1990s), in a galaxy far far away (West Moors), I bought a replica airsoft Glock 17 handgun. It looked incredibly realistic. Sadly, things have changed in the world. Nowadays replica weapons have to be made in bright colours so they can't be confused with real ones. They're not really 'replicas' at all.

More recently, to accompany my DIY Boba Fett costume, I bought a toy Boba Fett rifle. If you're familiar with Star Wars, you'll know that his rifle WAS NOT white, orange and green. I had to paint the thing black before I could be seen in public with it. My friend bought a small pistol to use with a Han Solo costume, and again had to paint over the bright colours.

A gun is a gun, and if it's a toy gun, it's still supposed to be a gun. If you're at a fancy-dress party as Al Capone, there's no point carrying an orange gun. It's clearly a toy. You might as well be brandishing an Action Man or a game of Tetris.

 

a

My only concession to the colourful toy rule is that the inside of the Breech is still orange, because I forgot to spray the cone from both ends.

 

Shopping list:

5ft of 1.5" black tubing
£1.50
Homebase
Toy Gun (large)
£1.00
Charity Shop
Wood design sticky-back plastic
£1.00
Poundland
Skittles game with traffic cones
£1.00
Poundland
Large Terry clip (wasted!)
99p
Hardware store
Water Pistol (small)
50p
Charity Shop
Dog Lead
£1.00
Poundland

Miscellaneous found items:

Ice cream lids
500ml drink bottles & caps
Plastic Cocktail Glass
Small Shelf Brackets
Assorted tubing
Cereal boxes
Green paint*
Black spraypaint
Chrome spraypaint
Scrap of wood
Black cord
Shoelace
Lego bits
Keyring Clips

Stuff everyone should have:

Sellotape
Superglue
Black electrical tape
Stanley Knife (and plasters)
Handsaw
Scissors
Cable Ties

Absolutely essential:

A bit of imagination

* I had the green paint left over from my Boba Fett project, but you can buy 2 litres of it in Poundland (for a pound). The black and chrome spraypaints can also be found there.

 

One of the reasons I have these projects is that it gives me something to do at lunchtime. It's a lot of fun to be scouring charity shops or raiding Poundland for things I could use.

Another reason is that I like to keep my mind occupied, all the time. Doing this certainly beats Sudoku!

 

Other Projects:

Boba Fett Costume
Han Solo in Carbonite bookcase
Radio-Controlled MSE-6 Droid
Jawa Costume
Batphone

You may notice a slight trend in my project ideas.

 

"Imagination is more important than knowledge."

Albert Einstein, 1977