Check out the DFC on this one

[Mad Max]

Horn bow with big heavy Siyahs
Check out the DFC  (13 &14")
 "It was only when we tested this bow that the facts and figures started to impress again. At 82 pounds its draw weight started to outperform the disadvantage of the weight of its ears, results were impressive. The 82# Manchu bow, made by Wen Chieh, outperformed a well-made 128# yew longbow, shooting the same 1230 grains (80g) military weight arrow a stunning 190fps against 170fps for the longbow".

http://www.manchuarchery.org/bows

[Flem]

Those are some wild looking Bows! Thats some serious engineering to design and build those things.
I would like to see a video of someone stringing them up.

[Mad Max]

I always wondered how they shoot with all that mass on the siyahs.
Some of them can be pulled back against your knee with a buddy to put the string on.