Different wts different actions

Last summer a bought a 6wt rod from a major manufacturer. I love the rod and it is my "go to" rod when I need a six weight. My nephew bought the same model only in a 3 wt. When I casted my nephews rod, it seem to have a totally different action than my 6 wt. I know that line and weight can make a difference but the difference I experienced seemed to go beyond just the line and weight of the rod. Has anyone else had the experience of casting 2 different rods of the same model but different weights and having the action feel so different?
caribe

Yes several ,often time only a few in a series that excell ,such as Sage SLT 490-4 great dry fly rod. Sage XP I liked the 490,691,790.In the Light line series 389ll 586, I liked in G Loomis Glx classic most line weights.

Rod wts do make a difference ... a BIG difference. My main stay rod is a 5wt - have three of them: a med action 9' and 8' plus a 9' fast action. However, when I made my trip to Alaska for salmon, the ole 9' 9wt was the order of the day. Did take the fast action 9' 5wt, too, for the cutthroat on an inland lake. Compared, the 9wt is a broom stick to the 5wt, but the 5 is no match for big fish like the salmon we were after.

Yes, rod makers will often go with different rod actions within the same model series. Sometimes they even state this in their product literature. For example, Sage once used the following in their description of one of their rod series: "Throughout the entire line, we've created a taper and action that best fits each specific line weight."

These days, the rod manufacturer that seems to be the most explicit about specifying different actions within a given model series is Orvis. I know with their Helios rods, the would list them as either mid flex or tip flex and even have a flex number designation. I haven't checked a Winston catalog in a few years, but know that in the past they would carefully denote rod weight, length and action (slow, medium, fast) and even specify appropriate casting distances for each rod.

This is great information. I have always assumed that the different weights in the same model would have relatively similar action. That being said, I do not own any rods of the same model in different weights so I had nothing to compare. This tells me that it is really important to cast the rod before buying and not just relying on a similar action in a different weight.
caribe

Rod manufacturers design the rods to perform best for the use the rod is likely to be put, even within the same series. The way the typical person would use a 3 wt is different from how they will use a 6 wt or and 8wt. In a 3 wt, presentation is usually key, so the action will likely be slower. Once you get to 6 wts and above, distance and butt strength are more important, thus, you tend to get a faster action. This is also why you see comments that upper weight rods are "under rated", because people have to overline them to get close to the same action as the lower weight rods.