IT was not that Excalibur did not have to build a faster bow ........ Bill Troubridge has always said that he could build faster bows, that he could easily hit the 400 fps with a bow .... but at what cost. HE would not rist the safety of the shooter or the dependability of the bows he produces. The Exomax was tested for years before he decided to put on the market. As I said abiove ....... Crossbows store energy in the limbs, faster means more energy stored. More energy stored means more stresses on the bow and parts. This now brings it to the recurve / compound choices. With he recurve aspect, there is just the limbs and string, but with the compound, you have limbs, cables, pullies, cables, pins ect, that will have stress applied to them. Also remember that with the crossbow, all of this is in a very narrow (width wise) package, not like in the vertical bows which I believe went longer to lessen the stress on the pullies. Short tends to make a violent shoct while long makes it a gradual shock.

Hope this helps you.