Just to add a little, I tried the No 5 on 2 type IV arms as well as my IV.5i and none would fit the cartridge. Down the road I acquired a 309 for other purpose and was surprised to find that the No 5 fits OK on the 309.
The drawings on the old SME website for the IV and the V are/were identical.
I am surprised that Mike's No 8 wouldn't fit on his V. I have to assume that SME arms are identical within their model type so does this point to the cartridge bodies as having irregularities in diameter?
Too bad that the Jo No 8 had to be returned. I have one and it is a really good sounding cartridge.
Bill