
The reality seems to have been pretty grim:
www.telegraph.co.uk/news/worldnews/asia/northkorea/11572789/Satellite-images-capture-North-Korea-executions-carried-out-with-anti-aircraft-guns.html
The basic idea of these canons is to intercept and tear apart fast moving metal objects - planes. It's pretty unimaginable the effect on flesh
( , Wed 13 May 2015, 13:34, Reply)

canon
noun
(Christianity) a Church decree enacted to regulate morals or religious practices
(often plural) a general rule or standard, as of judgment, morals, etc
(often plural) a principle or accepted criterion applied in a branch of learning or art
(Roman Catholic Church) the complete list of the canonized saints
(Roman Catholic Church) the prayer in the Mass in which the Host is consecrated
a list of writings, esp sacred writings, officially recognized as genuine
a piece of music in which an extended melody in one part is imitated successively in one or more other parts See also round (sense 31), catch (sense 33)
a list of the works of an author that are accepted as authentic
(formerly) a size of printer's type equal to 48 point
( , Wed 13 May 2015, 17:58, Reply)