"Elightened trial and error" was the method used in the beginnings of the study of metallurgy because they really didn't know what the effects of adding a little of this element or that element would do to the microstucture of the basic material, and hence its physical properties in a real world environment. It was pretty much, "OK let's see if this works" and over a lot of decades there were enough 'happy accidents' that strides were made in the right direction. Once metallurgists had enough root knowledge gained from previous generations of study they became able to use "planning and flawless intellect" to correctly predict what the outcome of adding a particular element would be. Also their methods of testing matured to the point where they weren't just shooting in the dark anymore.
Its a shame but most of the big leaps in metallurgy have been driven by war and paranoia, and warplanes are a good example of what we're talking about here. First they were made of wood, then they were made of Aluminum because it was stronger, and these days they're made of Titanium and carbonfiber for the same reason.
Now if you prefer to keep yourself in the dark when an advancement in knowledge is presented to you on a platter, then so be it.
Hopefully there are others reading whose minds aren't so closed.
Good choice, you obviously did some research. Stronger bolts of the same diameter and length don't weigh any more than the weaker ones, so there must be something else happening if they're 10 g. heavier. For future reference keep in mind that Carrillo uses one piece forgings so the grain structure is all wrong in the cap. Cunningham uses 2 separate forgings so the grain structure is correct in both parts. And Cunningham rods cost less too.
I can start a list for regular shelf rods... I have some weights written down somewhere. I will try to update this over the next couple days.great info on this thread but it would really be helpfull if someone gave some info on the weights on the rods itself.