What would be a good alloy/ dimensions for an aluminum blowgun?

I would like to order an aluminum tube from McMasters.com but I'm not sure of what kind I should get for a blowgun.  If you could put in the dimensions you would get for a blowgun at http://www.mcmaster.com/#aluminum/=7mdkul that would be great, thank you. 

The only set thing I need for the tube is for it to be less than a .50 cal blowgun...

If you could tell me if this would be good for a blowgun that would be great: http://www.mcmaster.com/#aluminum/=7mdm28


                                                                                                                      Thanks,
                                                                                                                        Wafflicious

Comments

[Owenmon]

OMG

[Wafflicious]

lol