[Unclenick]

That much change will have a small effect in that the stubbier design will be pushed deeper into the case by a fixed seating stem. That will cause a small pressure rise. It will change bullet jump to the throat, as well, which affects accuracy, so you may be in for some retuning of your load, though you also may not.

The longer bearing surface and shorter ogive, unless the boattail was changed, too, would have greater volume, so they may be leaving a bigger hollow for the plastic tip. This would reduce the transverse moment of inertia of the bullet, making it a little easier to stabilize, so a little less twist could be used (in theory, but I'd have to measure the transverse moment of inertia to tell how much difference it makes).

The sharper shoulder indicates the ogive is a secant ogive on the new shape. Secant ogives generally have a longer ogive radius, giving them lower drag for a given ogive length than the older tangent ogive does, so it is possible the BC is unchanged.