The .303 has a bit less pop than a .308 Win,so its effect on animals should be very similar.

The .308 shoots a little flatter,has a little more velocity and hits a bit harder.

If I already had a .308,I wouldn't be using the .303. The ammo is limited and like I said the .308 is better all around.

IMO the .303 would be a gun to take out just for a fun day at the range.