bringing up an older topic...PVC barrels with CO2

[JDP12]

hey all-About a year ago I made a topic about using PVC as a barrel with CO2, and it kind of died because I didn't really need it anymore..

But now I do so I'm making a new topic.

This gun is going to be an undermount for paintball on my a5. The chamber volume is ~~3 in^3, and all steel. This will be used with unregged CO2 because that's the only way I can get enough power to push the balls far enough or hard enough to break with that small of a chamber.

It is a coaxial style gun...

And right now using all steel it is incredibly heavy, probably too heavy to actually be able to use.

So I was wondering if I could use PVC as the barrel- 1.25" to be exact.

The ammo is only about 9 paintballs wadded with paper towelling- no tight fitting ammo. Also maybe 2 oz paint grenades.

I was going to sleeve the barrel in 1.25" couplings just as another precautionary.

What do you think? Really i'm not using tight fitting ammo at all... not even air-tight really.

Just want to double check before I proceed with it...


EDIT: I may just use all steel and suffer the consequences of like a five -eight pound undermounted grenade launcher.... Cuz I really want to err on the safe side.

[thedeathofall]

well, a picture of this steel cannon would be awsome.

I personally would be careful about unregged CO2. It may still be very cold when coming out the barrel. possibly cold enough to cause damage to the pvc. I may be wrong, but it never hurts to be too careful.

To test this theory, use the steel barrel and fire it multiple times as fast as possible. If the barrel gets too cold to touch, or starts to frost, then forget about pvc.

Other than that, i dont think you will have to much of a problem... how long is the barrel?

[ALIHISGREAT]

You could just make the switch to HPA?

[Hubb]

I've used PVC barrels with CO2 and have never had a problem. You are not going to fire it fast enough to chill the barrel and the barrel is not going to be holding any pressure.

I wouldn't use thinwalled pipe, as the pressure spike may break it, but I've never had a problem with Sch40 pipe as a barrel. I usually go with 2". If you are using 1.25" there should be no problem.

And, besides, if you do feel that the pipe won't be strong enough, I've also used aluminum conduit pipe. It strong, durable, and a lot lighter than steel.

[Biopyro]

Are you worried about the pressure or the pipe getting cold? Because HPA gets cold too!

Neither will be a problem, because it's the barrel, which doesn't take much pressure. The gas will take the path of least resistance, which is pushing the paintballs, not cracking your (rated) pipe.

Don't worry about it. With such a loose ammo, it just won't do anything.

[spot]

It is a coaxial style gun...

If I understand correctly, you're going to put the barrel in the chamber.
This means that the PVC will have to hold pressure... Although it's pushing from the outside (this makes it handle more pressure) I don't think it's very safe.

Note: If I misinterpreted it and it's not going to hold any pressure, I think it's safe too.

[Biopyro]

My mistake, didn't see it was coaxial. I which case, yeah, you need something rated to around 800psi. (1.25" PVC SCH 80 is ~600psi)

[JDP12]

no the coaxial part is steel... only the barrel is PVC. its hard to explain.

Thanks guys, this should help alot