Two posts asked if the search was for .303 Brit or .303 Savage, though the OP's picture is clearly .303 Brit. Unsettling but reaffirms to not take Internet traffic to be completely accurate, even mine.

Several have suggested reloading soft points if commercial ammunition cannot be sourced, a reasonable solution if current commercial .303 Brit cannot be found. I haven't seen any for many moons. It was not common before the pandemic. Suitable soft point 0.311 bullets might be harder yet to find. Haven't seen those in a while. A last gasp desperation move would be paper patching 0.308 bullets. Ross Seyfreid published many successful accounts of his use paper patching to get oddball calibers shooting.