The last 190 grain loads made for the 303 I'm aware of were Winchester Silvertips. These loads would work fine on deer, but with a thin jacket, they opened up quite quickly, making them marginal for heavier game.
Considering that the 30WCF has worked fine on deer for 100 years with a 150-160grain bullet, want to tell me exactly what the extra 30-40 grains are for?