SpudFiles

Hi there,

Myself and a friend are going to attempt to build a few guns with different styles. Seeing as we are only starting out, we are going to attempt to build a small handheld gun that shoots frozen peas or something similar.

I was wondering what the recommended length of the chosen pipe should be? would 4/5" be sufficent for ample power?

Regarding the container, does the size really matter? As long as the pressure is the same, shouldn't the power of the gun be similar?

Sorry if I'm being stupid here but I'm not a scientist, just love building things like this and want to learn more.

Thanks! 8)

As far as the size of the resovoir (call it that, it makes it easier to understand) it has to be the right size in relation to your barrel. If you have a 4" diameter barrel that is 3 ft long, youre gonna need a big chamber because when the projectile gets pushed up the barrel, the air has more room toexpand and lowers the pressure. for something as small as frozen peas (i wouldnt recommend shootig them cuz theyre all wierd shaped and wont make a good seal in the barrel) your resovoir would be much smaller but large enough that the air could go out the barrel and not lose mush pressure overall and thus achieve a very fast speed. All of this is assuming you want to make a pneumatic. Another thing, id suggest that you check around spudfiles first before posting, there are TONS of plans here and on the internet. just google pneumatic potato launcher, gun, cannon,etc. plans. hope i helped

How about shooting airsoft bb's if you can get them. They would be a much better projectile than peas.

Thanks for the replies. Now I understand why the chamber must be bigger, makes sense now

Is there any reason for having a larger reservoir? surely shorter the better, unless you requrie pinpoint accuracy? or am I completely misunderstanding it (probably the case)

I will find suitable ammo however I was mainly giving an idea of the size that I would like it to be, much like a hand gun size but slightly bigger

Thanks again!

I don't think your understanding it...

#1. Is your gun is going to be using Compressed air, a valve, and a barrel to shoot (pneumatic)? If yes, goto #3... If no, goto #2

#2. Is your gun is going to be using Gas that ignites for pressure to shoot the projectile? If yes, goto #4... if no, goto #hell

#3. Bigger chamber will mean more gas... the more gas, the more flow there will be, thus making the projectile go farther....

#4. Bigger chamber will mean more expansion and more room for your Fuel to take up, creating a bigger flame and more pressure...

Overall bigger chambers (reservoir) means more room for gases, which means there's more stuff to push out your projectile...

Chambers gigantically big will give diminishing results because they won't improve your performance enough for how much extra fuel they take.

#hell.