go to your bike shop again and ask for bigger balls or try somewhere else... 6mm would be ideal for plinking...

use a blowgun as a firing valve, ball valves are very akward to use on minipneumatics and they have very poor performance, especially with light projectiles...

IMO it can be done but it's not worth trying - a 3mm projectile would have max range of < 100 ft. because the lighter the projectile is, the faster it slows down....

those co2 inflators look good. Do they have a built-in regulator ? anyone knows how high pressure is possible with one of these?

wow it sounds interesting.....
can't wait to see some pics&videos

I meant that greater caliber = greater bolt surface = more force acting on the bolt.... anyway it would be nice to see a fully auto 12.7 mm spudgun... :D JSR are you going to use the air on the other side of the bolt/piston to slow down the bolt ? (as a kind of an air spring ? ) i suppose that some ...

JSR I suggested you in your post that your design would work better with greater caliber - but yeah this is exatly what you are looking for

hope it's gonna work

It's a pity it has to use external power - I liked simplicity of this design....
I suppose it would work better with greater caliber (greater bolt surface) but i understand that scaling it up would make everything more air consuming and difficult.

jackssmirkingrevenge wrote: I fired about 10 test shots and not once did the bolt show any inclination to move back.

Ohhh that's suprising.... maybe the rubber band is to strong or the pressure is too low...?

anyway, it looks nice

yeah that is why people use helium or hydrogene... but I want to know how they do it (how they use steam in spudguns).
GGDT shows ~ 30% power increase with steam... so it's interesting.... and seems more practical and reasonable than 3000 psi spudguns

great gun....

I hope u can use longer barrels... 36" seems a bit to short with this chamber

yeah maybe... but you can use it whole day and it gives you more time. I can connect the compressor to the gun and go search for some ammo and load it... the only problem is that as it gets close to 300 psi my shreader adapter disconects itself from the gun.... but I like it since it is a kind of sa...

ragnarok thx it's good someone mentioned that... i've noticed that a lot of people here that want to use > 1000 psi pressures... and usually they haven't used more than 300 psi yet...

BTW GGDT shows that you can improve performance greatly with if you use steam.... has anyone tried that ?

I seems to me that the next round would be fired before the pin returns to the ready-to-fire-position.... I think that rounds are going to put a lot of stress on the locking pin - I suppose that the pin piston diameter has to be > than diameter of round.... becasue the force pushing the ammo is tran...

yes basically the same principle. The difference is that my design most likely has to be limited to semiauto and requires a QEV (as a main valve) triggered by a sleeve valve - to make sure that there is enough time for the bolt to be pulled backward before the pressure inside the chamber would rise ...

I have an idea that is very simmilar to your design the difference is that the spring is used to pull the bolt in order to load new ammo and insted of an electric drive a piston powered by air from the chamber is used to hold it in forward position. A cylinder or syringe that uses the pressure insid...