[rubbinisracing]

I wouldn't recomend either of the 2 grades/types of chain that have been mentioned in this thread.

"Proof Coil Chain": is very low quality and is better known as Grade 30 or Sysyem 3. The next chain up the the gradient is Grade 43 or System 4, this is the minimum grade desired for safety or tie-down. The best chain is the next grade up, Grade 70 or System 7,also known as Transport chain, with this chain the next smaller size has the same tensile strength as the next larger size of System 4. In other words, a 5/16" System 7 chain is equivalent to a 3/8" System 4, Grade 80 chain or System 8 is required by OSHA/MSA for overhead lifting, it works well in this application but is not suited for shock absorbtion or tie down use.

As far as Stainless Steel balls, you need to know what type stainless the ball is made from. Austenitic (300 series) stainlesss is very resistant to corrosion but can't be heat treated, it's tensile strenght is equivalent to a grade 2 cap screw. Martensitic (400 series) is less resistant to corrosion but can be heat treated. 400 series stainless cost less than 300 series. After heat treatment it is equivalent to a grade 5 bolt in tensile strength. There are other S/S available but you most likely won't see them available in these aplications.

Personally, I would stay away from "cast" balls and use only forged or those machined from a solid piece of steel and then heat treated.