Originally Posted By: Der Ami
I believe this is the 380(Long or Rook), which uses an outside lubricated/heeled bullet;whereas the 360#5 uses an inside lubricated bullet of smaller diameter.


You must be right about my bullet being for the 380 but the 360No.5 did have an outside lube heeled bullet. At least that is what Hoyem and Colin Greenwood say in their books and original cartridges certainly look it. The diameter should be .366".
I wonder if pushing mine through a sizer would ruin the heel.