Anyone care to guess my weight?

[Parashooter]

The 230-grain weight in .303 British isn't familiar to me. Who produced them?

I imagine you're familiar with the many 215-grain versions, the military Mark I through Mark VI as well as the sporting loads most commercial firms produced through the middle of the last century. Here's a Remington-UMC 215-grain sporting round from about 1955 (shown with a current-production 180-grain bullet) -

[rugersworld]

What the heck are you culling that a 150gr bullet in the right spot won't kill? And how far are you from the animal when taking the shot that bullet weight will have a significant effect on velocity and trajectory to target?