thats because its in /data/library: shells.zon, BUT you will first have to find the parentid of the shell you want to edit, in shells.dat that corresponds to the ammo type, i.e. 4 50, 20mm aa, whatever.in exdample the 40mmAA shells id is 0x805a0032af6ada0a then you look for that in parent id of the .zon. hope this helps you out. alternatively, here is some of the work allready done for you,
http://www.subsim.com/radioroom/down...do=file&id=517 there is a 25% upgrade in power, and 50% in RPM also 50% and 50%