The 400 Speer is soft as chewing gum, it will expand wide at 1900fps. The 350 Swift is designed for 45/70 speeds and will expand at any reasonable range. Up close the front section may lose some weight but not much. The 350 Hornady will also expand at 45/70 speeds, it’s billed as a 458 bullet but I’ve had it come apart at 458 speeds.
I’m a little confused by your concern of bullets not expanding in time? Are you indicating you’re worried the bullets will zip through without having a chance to open due to the close range and higher velocity? If that’s what you mean you have no need to worry, the faster a bullet is traveling when it hits the quicker and wider it will expand. If that’s not what you meant then disregard as I’m just confused.
