Try Fastenal(sp?). I got two 7/8X14 Grade 9 bolts(all they had) a couple of years ago. They come in handy for more than just seating fire lap boolits. I used one to lap the threads in two Redding T-7 turrets. Threading/tapping cast iron leaves a rough surface that really grated on me when threading in a die. Took awhile but now dies go in slick.

I won't be trying to modify these bolts since they are HARD/TOUGH. I kept the box they were in just to prove there is such a thing as a Grade 9 bolt.