Interesting tool - That's a new one for me.
Many years ago (60/70's) I worked on a Shell tanker, she was about 70,000 tons and our job was to meet the really big 200,000 tankers in the Channel, steam alongside them and relieve them of cargo so they could continue up the Channel to Rotterdam etc.
One of my jobs was to shoot a line across to the large tanker. The line throwing equipment was a No 4 Lee Enfield .303 with a full pistol grip grafted into the stock and a thick rubber girly pad on the butt. The line was 4mm nylon about 250 metres, this was attached to a steel rod about 10 inches long with a brass eye and just slid down the barrel.
The charge was a .303, not crimped, just sealed with black hard wax. Quite an experience shooting it and no trouble shooting the line a couple of hundred yards.
Obviously not a "blank" but a full charge of something.
Well I never! Not thought about that for 40 years and just found this:
http://cartridgecollectors.org/?page=co ... e-h-mark-2