straight from Hornady Manufacturing
#44200 240g XTP-HP 900-1800fps
#44280 300g XTP-HP 850-1900+fps
So both expand at lower speed; more speed opens them sooner.
Hardcast bullets just make long holes.
The perceived advantage to the heavier bullet comes at extended range, where its greater momentum allows it potentially greater penetration.
"all my ammo is mostly retired factory ammo"