I don't know how much a .450 No2 Nitro Express cartridge costs, because no matter what I have one to feed.

The brass is horrendously expensive. If they can be re-used several times the price will decrease per shot. Only Bertram and Horneber make brass for the No.2 I believe.

It IS 3 1/2 inches long, not 3 1/4.

I use a grey foam filler, two or three cut pieces stuffed into the top of the powder so the base of the bullet is up against the foam. Originally it seemed to disintegrate but I have been finding perfect foam pieces on the ground more recently. One of them even was stuff to the hair of one of my buffalo if I remember rightly! It was close range shooting!

You will need a big press for the 3 1/2" No.2. It will not fit into the average press at all.