I found about 2 meters of 3/4-20mm brass tubing under my house about a day ago,it looks really nice when its been buffed up so I'm thinking of using it on a launcher of course.But not just any launcher,a pimped out launcher

.Copper,brass,chrome in an over under piston design sounds great to me.
Does anyone else have any Ideas what I could use the pipe for apart from a nice chamber?
This gun is actually something that is "do able" in my books now due to my next door neighbor,so a silencer is probably needed and it's not going to be overly large so it can be hidden/stored easily.