SpudFiles

Today I found a store that sells copper pipes, and steel pipes!
I want to know what can hold more pressure, i don't really care
about the price.

For your purposes, the pressure ratings of such pipe is probably irrelevant, as it doesn't become much of an issue below 1000 psi.

Copper retains its strength at lower temperatures, is easier to modify, and generally fails safely (doesn't fragment).
Steel is generally stronger, comes in bigger common diameters, and is easy to assemble.

What is it with you and your constant "I must have as much pressure as possible" - then proposing designs with ball valves in them?

Let's get this entirely straight:
A good valve is far MORE important than high pressure.
If you can have both, that's great - but DO THE VALVE FIRST!

High pressure is completely wasted unless you have a fast opening and decent flow valve. You can do more with low pressure and a good valve than you can with high pressure and a rubbish valve (and ball valves are pretty damn rubbish)

Don't fuss with higher pressures unless you have something at least as good as a piston or hammer valve, anything less and it's wasted.

Also, unless you plan on piping in air straight from a SCUBA tank, the pressure those particular materials are likely to be able to take is fairly irrelevant.
We couldn't comment anyway without knowing more about the pipe - the dimensions and design are of far greater importance than the material in this case.

EDIT: Clarification of a point that could be dangerous if misunderstood.

Well, you could always have a slow valve, high-pressure and a long-assed barrel. I like to call it the Mythbusters approach

But I'm going to agree with Rag simply because that solution is not only unwieldy, but will become VERY expensive using metal parts.

Copper is typically more expensive than steel, and generally comes in smaller diameters. But they both have their advantages and disadvanages, so it's really a toss-up. I think ultimately steel will hold more pressure than copper, but you'd probably never even get close to the limits of either of them.

steel is heavier, and copper looks cooler =)
Gets very expensive in diameters past 3/4in.

I can only agree to rag...What gun do you want...post a picture or maybe an explaination, then we can help(if you want to shoot at targets scattared across an area of 50miles then you would want a light weight gun while if you want to have this massive piece of stuff for you back yard then steel wins hands down...)

I propose a mix: copper barrel, steel chamber/tees/etc. there are copper threaded adapters, you know. Copper pipe is smoother inside than steel, thus making a better barrel.

ramses wrote:I propose a mix: copper barrel, steel chamber/tees/etc. there are copper threaded adapters, you know. Copper pipe is smoother inside than steel, thus making a better barrel.

I know that copper is smoother inside,
and, Btw, all the pipes i'm using are threaded.