Originally Posted by HTupolev

I'm skeptical of your math.

The unthreaded portion of an M6 bolt has a cross-sectional area of about .044 square inches. High-strength 316 stainless hardware is usually rated for a minimum ultimate strength of around 110,000PSI, which over .044in^2 gives about 4,800 pounds.
But the threading also eats up a ton of the effective diameter. Realistically I'm not sure anyone should be counting on a coarse-thread M6 bolt to have an effective loaded cross-sectional area of much over .03 square inches, which gives 3,300 pounds.

Furthermore, stainless hardware often yields at far below its ultimate strength, so even "3300 pounds" is probably an optimistic perspective for most applications.