Geezer here: proprietor of New World Arbalest. Most of my Skane bows are made for combat games. Assuming you're using the 'baldar' type bolts with a shaft of 1/4 inch fiberglass rod, they'll give good service at@ 550 inch-pounds of force. They might also work for the siloflex 'tube' type bolts, assuming said bolts have a rigid enough rear-end for the string to work on. However, siloflex tubes are quite broad, and so might also need a bit of support at the head-end to keep them from falling off the groove. They will NOT work with 'Fellwalker' bollts. Check with your local SCA marshal concerning regulations in your area.
Geezer/David Watson, prop, New World Arbalest.