But you are mistaken, the cartridge is very much in production and for the cost of a new gun you could buy much ammo for your old .303.......
Not interested. Somewhere on this thread, or possibly another related thread, someone else came up with a good idea that I like.
Ream out the chamber of your old 303 british so that it will accept 7.62x54R russian ammo.
That’s a good idea. You can still buy lots of cheap surplus russian ammo. And there’s the added benefit that you can take a crappy old enfield rifle with bad throat erosion and turn it into a good rifle. This is possible because the russian cartridge is longer than the british cartridge. So when the chamber is cut deeper into the bore, the bad part of the barrel is cut out.
Presto! new rifle.
303 is junk as far as im concerned.