I might add here, that I shortened a bunch of .223 cases - spent primers still in them, annealed them to the base, filled them with lead, rounded the noses in a round nose Lyman top punch" and shot them in my first .376/06IMP.

They'd group into 1 1/2" at 100 meters, a bit better than the 350gr. Barnes heavy jackets. These home made bullets weighed 340gr.. With a pure lead core the expansion was quite lovely in wood, but with a WW core and non-annealed case, they'd penetrate almost like FMJ's - albeit with about 1" cavitation (permanent cavity) in the Doug Fir rail ties shot length wise.

Similar 'hard' .458 bullets made with .250 Savage and .303 brass made 1 1/2" cavitation holes in the same test material.