GBinSC, if you are satisfied that your rifle is OK, will you please excuse us whilst we ponder your question in some detail on the Ammuntion Forum?
I'll create a new thread in the forum shortly, and move this discussion there, as it isn't specific to Enfields anymore...
Go here!:
Maximum Safe Radial Expansion for Brass Cased Rifle Cartridges - Military Surplus Collectors Forums
Link above: the line disappears if nothing's below it.