Agree, they could be Sweetland Forgewoods. I've got some that are 19/64. They were manufactured in 17/18/19/20--64th's according to the check box hang tag on the mint condition, new in the box dozen that I have. You can do a simple test to see if they're Forgewoods. Take one with no point on it and find the balance point. If it's closer to the front end of the arrow, then it's probably a compressed 'forgewood' arrow. The process to make a shaft was to take a 'club like' block of wood (twice as thick on one half) and compress it to a uniform plank that was dowelled into a shaft. The end of the shaft with the denser wood is to be made into the point end of the arrow. If they are forgewoods, it's a great find. They take a beating.