I have read on here of someone being able to push the 300 grain .411 bullet up to 2600fps (in a 20" Bbl.) from a cartridge I "Believe" was the .411 Clopton.
I don't know of this cartridge, and would like to learn a little about it.
I have somehow been led to believe that it may have the 376 Styer as it's parent, but I cannot confirm this.
Any info would be great..!