I owned a Westley Richards droplock in 303. it was the best shooting double rifle i ever owned. when i shot it at the drss shoot & hunt in Texas last year comments were made that i was the only one who put the bullets in the center of the bull !

you can tinker with all your theories and try many experiments and basically you are shovelling shit against the tide ! wake up and accept reality.

just use the standard 215 grain round nose and you will never have a better shooting rifle. plus you can buy replacement ammo if yours go astray while travelling.

don't try to make the good old 303 something it isn't. just learn how to use it and it will never let you down. from stags in the highlands and stalking fallow deer in wales, roe deer and boar in europe plus plains game in africa you couldn't ask for a better all around cartridge in its class.
mine was there, did what i needed and did it well. you can experiment for years or just enjoy a great cartridge as it is !