I reload for mine, but there are some problems
with reloading for the .303 SMLE.
The British made the chambers extra large
to allow the chambering of dirty, muddy,
even corroded rounds.
This means that when you fire the brass,
it swells a lot.
When you then resize it, it really "works"
the brass and can lead to incipient head
In fact, today as we were shooting, I had
a brass head seperation.
You pay a price for "reliability"
in chamber size.