SpudFiles

Firstly the 4mm barrels are 60cm fibreglass tent poles with an 8mm OD and a 4mm ID and the yellow coupling used to join them is a cut down and dremel lathed core of one of these:


A picture walkthrough of the build












The darts are the brass nibbed plastic tubes inside ball point pens with the rear end slit a few mm and flared out. They can punch through as many cardboard boxes as you can be bothered to put in front of it or through a 5mm softwood plank

hehehehheheh kool

very nice. looks professionaly great!

nice. can you still have its old barrel? or will it be shooting pens forever now.

it must be very fun to cap cans and stuff.....hmmm may i ask you now how you get more than one shot off a fill?

have you though about putting a scope/sight on it?

Nice, though you probably could have joined a third length of tent pole and have a real high velocity penetrator, you certainly have the spare chamber capacity.

I can switch barrels on it still, the one I used for the outer shell of this had a tiny dent halfway along so it was pretty crap if I was using tight fitting ammo. It was just lying about so I decided to give it another go

I can also do nail darts with tape or unravelled string tails. Theres a number of holes through a 1/2" plank now... and a hole in my celing when I managed to press the trigger instead of the safety

Chaos I've not made my semi yet, the only hint I'll give is that all you can see on the cannon is all I'm using. Obvious perhaps but sometimes it needs to be said.

If you only exhaust a small amount of the pilot chamber, the piston will reseal before the chamber has time to empty, not sure if that's what you´re getting at...

I didn't notice your first post Jack: I already had the 1m copper barrel so it wasn't really possible to attach more poles after it - I have a suspicion the reduction of bore to 4mm is pushing the air towards the speed of sound - definitely a sharpish noise when firing.

You really should try going for higher pressure, with just 12 inches of barrel at 400 psi I had managed this.

It's a great design and I don't see why it shouldn't hit near-subsonic velocity with light enough ammunition. My only gripe would be the extra pilot volume but I suppose you have to sacrifice some performance for ergonomic´s sake

edit: another small tip, with higher pressures the pilot blowgun is going to harder to operate, perhaps an actual trigger would be a good idea to spread the weight over your finger and make it less of an effort.

I can feel the difference between 240psi and 0psi but it doesn't seem to be causing much of a problem - I wear a black cotton glove on my grip hand so my finger slides over the trigger as it's pulled instead of sticking.

A shock pump will be on my shopping list as soon as I find a way to attach it - I'm using a presta valve and shocks take schraders I believe...

yours for just 2.99 including delivery

I guarantee you won't have the patience to pump up a chamber that size with a shock pump. Even topping it up after filling it with a track pump will be an ordeal. Since you are using copper and JFC, why don't you make your own?

Hawkeye wrote:I guarantee you won't have the patience to pump up a chamber that size with a shock pump. Even topping it up after filling it with a track pump will be an ordeal.

Ordeal come on, where's your cojones? Besides, it's good exercise

Exercise shmexcersice, I do this for the fun of it

I've already got a couple of those things jack but the bloody things leak like hell

Maybe they're low quality.