BSP is a tapered pipe thread standard, and not a bolt thread standard. In the aerospace industry, there are ASME standards for both inch and metric "J" thread forms used for fatigue critical threaded fasteners. They both use a controlled root radius for the external threads, but other than having inch vs metric dimensions, they are not much different.
There are many other important factors when it comes to performance of a threaded connection than just the thread profile used. As others noted, materials and heat treatment, manufacturing processes used to produce the fasteners, design details of the fastener installation, quality control of the fastener installation, etc. all can have a significant effect.