We've had this discussion before, Chuck - in the past there may have been discernible differences but now they are the same thing. In some parts of Europe 2 1/2 inch .410 shells are call 36 cal and the 3 inch shell are known as .410 or 36 cal Magnum as per my original link - http://www.fourten.org.uk/36gauge.html.Chuck wrote:.36 is a (somewhat obscure) European calibre whereas .410 is - for want of a better description - American! They are NOT the same as these wee finicky semi autos will soon tell you.
That was the problem with the Safir: the .410 and 36 WERE decidely different as many people found out the hard way. It was intended to specify .410 ONLY for the UK but it never happened
One thing for sure, that wee slug packs a wallop at short range but maybe not for things like boar.
Also see,
http://www.chuckhawks.com/410bore.htm
http://cartridgecollectors.org/?page=co ... shotshells
Got to the bottom of this link http://www.cartuchostrust.com/en/cartri ... her-gauges for real confusion - referring to 36 cal as .410 gauge!