Back in the day I had a gorgeous Marlin lever gun in 32-40, and ammo wasn't available.Have you looked at Starline yet?
It can be made from 30-30 using 32-40 dies if you go carefully and use Imperial Sizing Die Wax. I have done that in years past.
??????I have all single shot rifles; Sharps Borchardts, HiWalls, and a CPA Stevens. I think it is a waste of time &
$$$$ to do a bolt gun.