u/caseylain

Basically I'm wondering if there is any PCP rifle that was designed to either use a tethered bottle as its primary air source, or has a fill port located where the hose would not be awkward to move with.

Most every air rifle I looked at either has the fill port way out in front, or sticking out the side away from the shooter. I think ideally a tether based rifle would have a fill port toward the back, pointing down. If it has a tank at all, it would be smaller tank that would act as a plenum.