PRVI will probably be .455 dia at the head and will be too big for your chamber.

I have not measured or even seen Hornady cases. It would be ok if no larger than .451 or .452 at the head. If anyone has any Hornady brass I would like to know the head diamter.

Both Remington and Winchester work well (.451 to .452) but they will need to be annealed after forming.

You might check the diameter of the open end of your FL die and your chamber to see what is going to fit.

I have worked on forming this caliber a lot. With the right dies I can get 100% good cases but I use more dies than most.

1.It is a good idea to shove the shoulder back with a .308 Win FL die but a 7.35 Carcano FL die works (.317 neck die dia) even better since it supports the skinny .303 shoulder a little better and prevents it from buckling.

2. Then I use a 6.5 Carcano trim die (.300 dia) with the shoulder set long

3. Then I use the 6.5X53R trim die (.290 dia)

4. Then I use the 6.5X53R FL die. (.284 dia) I strip the guts out of my bolt and use it to set this die so there is a slight drag on the bolt when closed. This sets the shoulder against the chamber shoulder and reduces case stretching. Just be sure you don't push the shoulder back to far with one of the earlier dies.

Necks do not have to be turned or reamed because my chamber necks (4 of them) measure .300.

If you find the Dutch drawings the dimension for the case length converts to 2.112". But my chambers measure 2.150" so I trim the case to 2.148 for the first firing. Since the .303 has a smaller shoulder diameter the case gets shorter when fired the first time. They will shorten .004 to .007. After the first firing I neck size and trim everything to 2.145.