Thread: best 303 ammo

What currently seems to be the best factory 303 ammo? The lighter 150gr stuff is advertised as going a bit quicker than the old school 180gr pills but do they and do they work any better? Unless someone gives me all the presses dies powder etc. for free I wont be reloading so please only consider factory stuff.
Also consider barrel length cutting back to 22" ish or maybe a little shorter ok?
Cheers.