I've been given several varieties of .303 British ammo but I have no .303 British rifles.  So most of the .303 got sized down in my tightest chambered Krag and it's now emergency Krag ammo, or it could still be used in .303 since headspace is on the rim.  I'd use it in a sporter that has a .3105 groove diameter barrel if I needed to.  Most is hunting ammo, but there's also some South African ball of WWII production.