Yes there is a small difference in the two cases. The 450 having a thicker web than the 45/70 means its cases capacity is just a little less, but will handle higher preasure better than the 45/70. Word of caution, Even different manufacturers of brass, Win vrs Rem etc. will varry on case capacity. Some times quite a bit. I once had a hot 45/70 load worked up in one case that I couldn't even compress in another brand. So be carefull and start low, and try to use the same brand of cases when you buy new ones if you can. KN