There are a lot of different woods called ironwood, being close to southern Ontario, your probably referring to Hop Hornbeam. They don't get very big in diameter, 8"-10" would be a big one around here, it usually grows very straight, but as often it is what we call, wind whipped, follows the sun, or it spirals. The straight ones make good bows, and arrows. I have made range rods from Iron wood, and osage, lot of work there! I think hickory is the best,its workable easy to find straight grain, and to me anyway, seems to have a better small diameter strength and flexibility. Just my opinion.
Robby