Swagelok, Parker, and most of the other fitting manufactures make fittings designed for 1/4" tubing for pressures much greater than any paintball
It looked like the lower fitting had moved a little on your picture, hard to tell.
But the line has pretty aggressive angle on it, so it
$300 for lowers + rail
$100 for body
$140 for valve
You can part the rail from the lowers as you see fit.