Originally Posted by
cxwrench
I'm guessing it says 'junior member' because you're young. Yes, I have. I've raced bikes for over 40 years. I've been a pro team mechanic and a shop mechanic for 25 years. I've worked with some of the best bicycle fitters in the world. I know of what I speak.
I'm not questioning your experience in any way, but I've dealt with stems which seemingly look similar to one another, but felt completely different in response.
to answer your question, they are often cast slightly different with different thicknesses of aluminum used.