Combustion Painball Gun

[jinxd]

Before anyone says anything, I know, don't shoot people with a homemade paintball gun, the ammo commoness is why I want to make one.

Im attaching a small, simple drawing describing my idea for the gun. Its a plain vanilla gun, nothing fancy, the usual RightGuard and grill peizo ignitor. The reason I'm posting is because I want to get it right before I waste money on the wrong things. I decided to use the male/female threaded fittings for later expansion (several barrels). Im also choosing CPVC for the barrel because from what I've read that is a perfect size for paintballs. Also, I calculated out the volume ratio with RatCalc and its ~0.81:1 (C:B). Well, I can't really elaborate much more... any suggestions or flaws?

[TalonXxX]

I wouldn't step down your chamber from 1.5" to .75" since 1.5" is small enough. I would step up your barrel from .75" to 1.5" That way, you are able to take advantage of your male/female adapters by adding barrels up to 1.5" without the restriction of reduced flow. You don't want your barrel to be larger than your chamber because that creates a bottleneck at the male/female adapters and greatly reduces performance. Your design is fine... I would just change the reducer coupling to be on the barrel rather than the chamber.

So instead of the 1.5" to .75" reducer on the chamber, put a 1.5" female adapter and then on the barrel, put a 1.5" male adapter to 1.5" pipe to 1.5" to .75" reducer to .75" pipe. That will allow barrel sizes up to 1.5" with increased performance.

[taterjim]

A 1.5" barrel on a 1.5" chamber would not work well .with that small of a chamber 3/4 " is about the largest barrel I would use. I wouldn't change a thing.

[jinxd]

Alright, thanks guys.

[jinxd]

The gun has been built!

Now, today I fire it and upload pictures.

[julz]

looking forward t o ti. would ya mind posting prices? im gunna make a combustion but dont want to spend a lot of money so a simple gun like this would b very good. thx

[jinxd]

Kind of a late follow up, but better late than never. :p

Only one pic for now, I'll take more then.

http://48hr.thewavelength.net/jinxd/pot ... ll-gun.jpg

[Cronic]

I have to say nice combustion indeed. Anyway how do you hold it because I don't see any room between the grip and the gun?

[jinxd]

You can hold it like a rifle, with the cap against your shoulder. It actually has a quite nice feel to it.

[guitarfreak]

You can hold it like a rifle, with the cap against your shoulder. It actually has a quite nice feel to it.

no no no no no,if the end cap blows off,you will get a broken shoulder

[boilingleadbath]

Guitarfreak, that's a pressure rated endcap. If he attempts any semblance of screwing it on, it will hold - most cap failures involve thin cleanout plugs (which are a terrible shape for holding pressure anyway) shattering, although there is the occasional event where one uses a non-pressure rated cap with some sort of odd threads (which these arn't).
The gist of that is that it won't "blow off".

[jinxd]

Plus, look at the size of the gun.