The new ST Epic's use a HP-insert,they are a 9/32" arrow and I haven't seen 100 gr inserts for them.The older plain Epic's were a 5/16" and you could use the 50 or 100 gr brass inserts in them.But the ST Epic's all they have is the HP-insert,you would have to make your own inserts.I took some 50 gr brass insert and mounted them on a drill and spun and filed them to fit some Heritage 90's.If your ST Epic was alittle weak you might have to get some 500 spine shafts so you can use 100 gr. inserts and tune them to your bow.If your Traditional only shaft are smaller you might have to make your own like I did for the Heritage 90.