Thanks for the quick answer. I hoped in a better blast at least but i'm not skilled in balistics so i can't say anything about that.
I wrote you because i played lots of wargames concerning italians tanks (i.e. Squad Leader, Panzer Blitz, Tobrouk of Avalon Hill, Bolt Action, Flames of War ...) and always the 75/18 Semovente's statistics are better than M13/40's ones.
I also read some informations on Wikipedia and in some historical book and again Semovente 75/18 is considered more effective than M13/40's gun Elefantino.
But ... fortunately it is impossible to test these weapons in real life so lets go to play !
PS ... anyway don't forget italians please
Thanks!