some update
105mm m900 m833 m774 m735
m900 - penetrator length 603 mm, volume 206344,9906mm³ (density 18,6/~3,830kg/real 3,830kg)
m833 - penetrator length 427 mm, volume 196634,2908mm³ (density 18,6/~3,657kg/real 3,668kg)
m774 - penetrator length 345 mm, volume 178942,0578mm³ (density 18,6/~3,328kg/real 3,364kg)
m735 - core length 309,5 mm, volume 119354,6819mm³ (density 18,5/~2,208kg/real 2,210kg)