According to Shigley's Mechanical Engineering Design Handbook, 9th Edition, p. 442, you have to consider values for preload as follows:
Fi = 0.75*Fp (For nonpermanent connections, reused fasteners)
Fi = 0.9*Fp (For permanent connections)
Fi is preload and Fp is proof load. You can calculate the proof load for different bolts as follows:
Sp is approximately 85% of the yield stress of the bolt material, while At is tensile stress area, which is calculated by (pi/4)*d^2. "d" is the nominal major diameter of the bolt, which is 5 millimeters for an M5 bolt. 316L stainless steel has a yield stress of approximately 170 MPa.
Note: This information is for conventional uses. For specific purposes, you have to follow the instructions provided by the supplier.