Pre-Build Pneumatic Questions

[DrowningTrout]

Hello, The main reason I joined these forums was to learn what I needed to know to build my Pneumatic Airsoft artillery cannon. I have been reading around and I think Im about ready to start, I just have a few questions...

Im planning on using airsoft easter egg grenades for the ammo (they are approved where I play, we will ignore how they work.) That was my first obstacle, easter eggs are 1.75" in diameter, not a common pipe size...So Im going to be using this:
http://www.onlinemetals.com/merchant.cf ... top_cat=60
Should this be ok? I will be threading it.

Next I needed to figure out what kind of re-loading configuration I wanted to use. I was thinking of using Breach loading, similar to what is found here: http://www.launchpotatoes.com/index.php ... oductId=40
But I would need a peice of pipe that has a 2" ID, Does anyone know what kind of pipe that is? Or is it a 2" Coupler with the middle sanded out?

Then what is going to be my C:B ratio? This is the part I am really struggling on. My air source is going to be CO2 (20oz paintball tank) So I want to get the most shots I can out of that while still getting good distance. Im wanting to shoot an easter egg 100-175 yards. I have no idea what length barrel I need and how big my chamber should be. So Please post any and all suggestions!

What kind of valve would be best for my situation? Was thinking a simple 1" Modified sprinkler valve, or should I use a Stinger Valve ect?

Also, This cannon: http://www.launchpotatoes.com/index.php ... oductId=49
Is able to have an adjustable barrel... How?

Summary:
Should that 1.75"ID x 2" OD Aluminum pipe be ok?
Would breach loading be the best for me?
What pipe has 2" ID or is it a coupler?
What C:B & PSI should I have for shooting easter egg 100-175 yards?
Guestimation on how many shots I can get with 20oz CO2 tank?
Wich valve is right for me?
WTF, does that barrel move?

Sorry for all the redundant questions, any help is greatly appreciated!

Thank You!

[biged]

You asked for a lot of intel.

Dimensions
The diameter of ammo will govern the bore of the barrel.
The weight* of the ammo will determine how far the ammo will travel.**
The porting size will be determined by the diameter of the ammo.
The piston size will determined by the porting size.
The length of the barrel is really up to you.
Barrel length will determine the volume of the chamber. (The volume of the barrel should not exceed the volume of the chamber.)

Performance
More pressure (PSI) more distance.
The bigger the valve the better performance.
The quicker the valve opens the better performance.

*The heavier the ammo the more dangerous/deadly it is.
**The pressure you use will determine what materials you can use.

///ed///

[Maniac]

You know you dont have to get that odd diameter barrel because all easter eggs are not 1.75. I have ones that range from 1-2in, just look around for different kinds. For your whole cb ratio/psi delimma just download GGDT it will solve most of your problems. For your reloading configuration just use what feels comfortable.

Also the man who owns and runs launch potatoes is a member of this forum his username is sgort(think thats right theres like two numbers after his name though).

[psycix]

A drilled out coupler would do the job for a "poormans breech" which is basically a hole with a piece of pipe (mostly a couper) slid over.

Is able to have an adjustable barrel... How?

The gun has a 2" threaded adapter, and so have all barrels. That way, you can screw on any barrel that has a 2" threaded adapter attached.

[DrowningTrout]

Thank you for the GGDT program!
I appreciate all the help!

A drilled out coupler would do the job for a "poormans breech" which is basically a hole with a piece of pipe (mostly a couper) slid over.

Is able to have an adjustable barrel... How?

The gun has a 2" threaded adapter, and so have all barrels. That way, you can screw on any barrel that has a 2" threaded adapter attached.

I don't want to be a poorman, just what pipe has a 2" ID?

I know how to change barrels, but how is that cannon able to move up/down positions, or is that what you meant?

[jrrdw]

The size the PVC pipe states is the inside diameter. You can use toilet paper wadded up as sabets for your egg's.

Would someone please put up the link to the PVC pipe charts, thanks.

Welcome to Spudfiles.

[DrowningTrout]

Im going to use the pipe for 1.75" eggs, since I have 100's of them and each grenade fully assembled only costs 16-18 cents. Wouldn't be realistic goal to make 100's of sabots.

How do I factor in Stinger Valve in GGDT or for that matter a sprinkler valve?

[jrrdw]

Isn't there a drop down menu with preloaded valve specs, just click on your valve???

[DrowningTrout]

Really the only question Im stuck at right now is... the Valve. I want good distance, but at the same time I dont need over kill and would rather keep the $$$.

Right Now my plan is:
-BARREL: 48in(4ft) 2" Aluminum Barrel (1.75" ID)
-CHAMBER: 3ft 2" SCH-40 PVC
-VALVE: Modified 1" Sprinkler Valve or Stinger Valve

This is a C:B ration of 1:1, Right?
Is this the most bang for my buck? I want to get the most/best shots out of my 20oz CO2 tank. If I need to change my ratio please tell me!