First thing I checked were the soles of my New Balance running shoes. 

That's a bummer, but you have two new ones coming!Was cleaning my 617-6, on my loading bench. Took the yoke screw out and removed the cylinder to make cleaning the ten chambers easier. Put the screw in a small plastic tray, open top, as is my habit. Moved some things around my bench to make room for the others, my Super Wrangler and my Wrangler Shopkeeper. Bumped the tray against something, and heard the dreaded "plink" as the screw hit the floor, I think. Thirty minutes of search under and around the bench, and it's there somewhere, but I can't find it. Even with a magnet on a stick. Bleah.
So who is a good resource to buy a new yoke screw? It's the new version, with the spring and plunger point. It's the stainless model.
Orrr...it just might have bounced into an alternate universe!Keep looking, it’s there.
Stainless can be funny stuff to work with.Just a thought, a 617 is stainless, would the bulk of the screws be stainless and not very magnetic?