POOR MANS CHRONO: SODA CAN

"There are six ranges of penetration on a Coke can. In order of difficulty they are:
One Side…………….290+FPS
Both Sides…………..340+FPS
Bottom Center………385+FPS*
Bottom Edge………...450+FPS
Top Center…………..470+FPS
Top Edge……………500+FPS

do not hold the can
align the muzzle of your gun 1-2 inches from the surface of the can

*According to RedWolf Airsoft this area is penetrated at 430FPS. However, in my testing, and that of others, we can consistently penetrate this area of a can at a minimum of 385fps."


taken from:
http://www.airsoftretreat.com/reviews/showproduct.php?product=71

No question about that and until now that system is still being use even here at the states if chrono is not available .....