SpudFiles

Back in September I won a competition on the UKSGC forums. The prize was free parts for the best cannon design budgeted to be built for £100 or under.

The parts arrived the week after Christmas and I spent the next three weeks building it.

Heres some pictures of it now (click for full size):



Breech closed, open and loading.




Makes a very nice vapour plume.


The control section. You can see the blowgun trigger, the presta fill valve (innards removed), the check valve and the safety ball valve. Oh and the nice neatly glued chamber end.




You might be surprised to know the barrel tees are not fixed. Its because its impossible to align them perfectly and because the torque put on them when replacing a 1m barrel can easily distort them if they're secured at the base. The barrel is clamped in place by the compression fitting securely enough to lift the cannon with it.



Details:

Chamber = 60cm of 22mm copper pipe
Barrel = 100cm of 15mm copper pipe
C:B ratio = 1.36:1
Pressure = 240psi
Range with potatos = 300m+
Range with specialised ammo = 450m+

Valve is a 1/2" QEV actuated by a severely customised blowgun embedded in and venting through the semi-hollow grip (you can see the exhaust hole in the base of the grip)

If you'd like to find out more about its background theres a heap of my design posts including a pile of all the changes and original designs that I went through before finishing at this at the UKSGC forum.
Keywords: copper rifle bullpup cannon air spud gun spudgun polymorph

AWESOME its amazing!!! looks devistating how much did u spend making this cannon?
id like to know how to make one ... well like yours

I love you... Really this is amazing! You are an awesome master with potato guns.

Damb Loverly.

that is one sexy cannon mate
nice work with the comp too

Lucky duck, won most of the parts in a contest! Congratulatins, you have done well with your prize. Do you have your compresion fittings flared or with ferrels?

Thanks

Brooner115 I spent about £15 on it. That was for ordering a check valve and a m/m fitting to attach to it to fix a problem with the presta valve. Everything else was given as the prize.

Nothing stopping you making one like it


To be honest this is only my second cannon. My first was just two bits of 15mm copper pipe, a ballvalve, a bike valve and a couple of compression fittings.

The difference between that and this was a couple of weeks of hectic research and design learning about valve types and various other bits to get a good design in for the competition.

In fact if it wasn't for the competiton attracting me in I'd never have got so engaged with spudgunning.

Jrrdw what do you mean flared or with ferrels?

This is the cleanest copper gun I can recall seeing. Good job!

Do you have a little ring (ferrel) you slide on the pipe after the flare nut?
Or does it have a bell shape to it (flared)?

Oh right, in the UK we call the rings olives and yes it does use them in the fittings.

The one on the chamber had the olive/ferrel fixed on with JustForCopper glue before it got screwed down to make sure it sealed properly but the barrel one is only hand tightened so the olive/ferrel isn't immovably clamped onto the pipe.

Like I said on Spudtech... NICE!!!

so clean and nice looking
very good job

Thats just amazing! and its only your second gun too! nothing like a nice, clean, well performing gun for a minimal fee. lucky UK citizen, i envy you!

i dont understand compression fittings could somebody plese explain.
do these fittings require and soldering?? how much for the QEV
thanks

~Petrie

that is probly the nices copper guns iv seen in a very long time it will be hard to beat

Petrie wrote:i dont understand compression fittings could somebody plese explain.
do these fittings require and soldering?? how much for the QEV
thanks

~Petrie

Compression fittings have a small metal ring which is then "crushed" around the pipe, effectively putting a lip on the pipe which then allows it to be held into the fitting.

@Hotwired: That's incredible construction work.

I can see a wrench in the grass on your "loading" picture. Any reason for it?