Well, even though he put it slightly in perspective, if you look at 0:35 of the video, he puts it to a ruler. It measures the length of the cannon and illustrates the proportions between the different sections of it. Try using that as a ref rather than the image you put there.
omg noice progress guyz, to szhark, i really love the cannon, its pretty polished cartoony texture :)! need to focus on one thing T_T..... :o i blame resonance of fate ..... dang ... and what the hell, its been 6 month i haven't touch my softimage xsi T_T
Sweet cannon :). Thanks snipergen. Katana, yah usually i would agree with you, but sometimes you just need to roll up your sleves and do work for the sake of practice. One more sitting left in this one... Im exited... this will be my first "finished" illustration since highschool... How i got a job without finishing…