What are the range of dimensions of boar or bear spear shafts?
Do they taper or are they barreled?
Any other details that are important?

Thanks

Boar spears are 6-7 feet long shafts. More towards 7 feet than 6 imo.
I think they are barreled not tapered. My reasons being that when hunting a boar you would want the possibility of placing the shaft on the ground rather than holding the shaft in the air when piercing trough an angry boar. If the shaft is tapered towards then end, the end piece will be weaker. It could be tapered wider of course if that is what you are asking? It is not something i have seen in any art though.

I realize now you were asking of the total length of the boar spear. With the spear head the total spear length will be 7-8 feet.