I've thought about something like this using pre-cast concrete drainage pipe (4 or 5 foot) ... making it to where it doesn't leak is going to be the biggest challenge. That and you really want your ventilation on the target end so it pulls all the nasty chemicals that result from shooting indoors (and there's a lot of nasty chemicals that end up in the air when you shoot a gun ... that's why just shooting a suppressed .22 indoors is a bad idea even though it's not that loud).
Honestly though, the cost of building it (and then tearing it out whenever you decide to sell ... you really don't want that big an "off permit" construction project to be discovered by would-be buyers since in addition you being forced to remove it you might incur the wrath of the local building inspector) seems to me it would be cheaper to buy some country property and build an outdoor range there.