Barrels have about 6 different stresses working on them when a gun fires. Barrels are made from forged steel and a technique called autofrettage is used to strengthen them.

Thank you, Could you be more specific on the kind of steel used? I am sure each cmpany uses a little different steel but there are families of different kinds of steel (low carbon, high carbon, other alloys)? In addition do you think that the autofrettage will change the steel's abillity to witstand penetration of bodies from the outside?

steel hardening is an odd beast. some countries use different methods - arguably (on average) the germans have made the best. in a twist of irony, depending on method used, the harder a steel becomes, the more prone it is to shattering or becoming brittle. the tech to strengthen a barrel is different from strengthening a panel etc... some barrels are one piece, some are sleeved, some are jacketed etc.... there are heaps of issues to contend with such as heat build up, heat dissipitation etc.. - also, it's not really a design parameter to build in resistance to being struck by an incoming round etc... as an example, (generally) because the russians metallurgy was at a different level than western technology, they favoured larger calibre rounds to compensate for an engineering difference. thats an oversimplification - but it gives you an idea of how build differences could impact on eventual design solutions. it's a really quite complex topic, and probably some of the arty or tanker guys in here could give you a concise overview

I am conscious that the methods used in the production of the barrels strength it from the inside, and i would like to know what are the effects of them to pressure from the outside of the barrels. I know this is a complex subject and thus i do not need a complicated diffrectial anlysis of solid state metals, but more of a thumb estimate. Inm addition does anyone know the type of steel used in the production?

"Inm addition does anyone know the type of steel used in the production?" no one will be telling you that kind of info on a public forum.

oh I dunno...The steel compositions of the various Russian and Chinese artillery and 100+mm guns should fairly well known by now... GERALD BULL KNEW, CL