As Jim says, the fired hulls should be the same.
Depending on the crimp style, the crimped shells may be different. Federals have crimps that look sort of rolled over on themselves. They're crimped with the plastic hot, I think. Remington crimps tend to look more like the crimps I use when I make shells myself; they're probably also done warm, though.
Anyway, the rolled-over crimps take up a bit more length than others. Different crimped lengths are influenced by the size of the wad in the shells. This can vary, since wads have a rather long suspension secion between the powder cup and the shot cup and petals. The design and length of this section varies greatly.
