It is an aluminum cylinder, .200 wall thickness, hydro tested at 2,200psi.
Even as light as a tennis ball is in respect to developing high chamber pressures-
I just wouldn't trust the Alum. barrel.
2,200 psi of a pressure test really isn't much in the scheme of things.
Also, Alum. work hardens, gets brittle, and develops cracks when you put much heat & stress on it.
For what you want to do, I'd sure hold out for a steel tube.
Or, order a piece of roundstock from one of these specialty metal dealers, and make it on the lathe.
Last winter, I mail ordered a 7" long piece of 6" roundstock for my powder chamber.
They sell steel pretty much by weight, my piece was about 60 pounds, and as I recall, about $75.
Yours would probably be smaller, lighter, and cheaper.
But you'd have a barrel carved out of solid steel that you'd never have to worry about.