Below is a post that I made to the nobody likes 4 weight thread that I think will help with the 904L.
“As you know, rod action is a bit of a subjective term. But, I thought I might add a little color regarding the Montana Brothers 904L. If one were to compare it to the old Paul Brown rods, it is true that it is stiffer. In case you are curious about those old rods, there is a neat thread here: viewtopic.php?f=3&t=13930
But, one thing those old rods suffered from, in our opinion, was the tips were too light. You had to be careful with the tip when casting them. They really demanded a very consistent stroke from the user. And if the wind come up, as it usually does here in the West, the tip demanded even more attention. So, we designed the 904L, to have a stiffer, more controlled tip. But, once you start stiffening up the tip, you will need to stiffen the lower portions of the rod to help support the tip.
Since many folks have probably never seen one of Paul’s old rods, here is another attempt at a comparison. One rod that I like to use is the old pre-IM6 Winston 9 foot 3 weight 2 piece. But I like to fish it with a 4 weight line instead of a 3. Winston labeled this model as slow in their catalog. The 4 made it even slower. If one were to deflect that old Winston in comparison to the 904L, the 904L will defect more under the same load than that old pre-IM6 903. If one’s opinion is that softness is determined by deflection under a load, than one could conclude that the 904L is softer than the pre-IM6 Winston 903.
However, I feel that deflection tells only part of equation. The other part is how the rod bends or accepts the load. The 904L has a stiffer tip and a softer butt than the old Winston. It has what we at MBR would call a more integrated action or a much smoother bend. If one’s only definition of a soft rod is that it has to have a light tip than maybe it would not be called a soft rod. Our definition is a little more holistic of how the overall rod would bend. I will also add that while the tip is stiffer, it is still supple enough to protect light tippets on big fish.
I am probably in the minority, but I have never cared for the term semi-parabolic as it relates to rod action as there seems there is some disagreement of what a parabolic rod even is among some folks. The late Paul Brown, disagreed with what is commonly associated with what has been coined as a progressive rod. I suspect that some of his rod designing friends felt the same way. To Paul, a true progressive rod was one that had a bend that started at the same point, and the bend increased as the load increased. One might argue that the 904L is closer to that description. The progressive term has really stuck and I don’t think anyone will probably be able to change that. We have jokingly called the action of the 904L as truegressive.
In response to the original post, I would say that I use a four weight the most for the type of fishing I prefer”
With respects to our regular 904, it has a stiffer tip and a softer lower half than the old Scott 904. Our 904 is more of what had been coined “progressive” than the 904L.
A few years ago, some friends and I cast the regular MBR 904 alongside a gen 3 Sage LL 904, a Pre-IM6 Fisher rolled Winston 904, and the current Redington Classic Trout 904. One might argue that the MBR regular 904 was the softest of the bunch, while another might argue that the Winston was the softest of the bunch due to its softer tip. However, the MBR bends more in the lower half than the Winston. It’s interesting to note that each of these rods have a similar static deflection under a load. However, the way that they bend under a load is different.
Sorry, but I have not handled or cast a Fries bamboo rod or a Franke rod, so can’t speak about comparisons with those rods. But, I hope this helps to answer your question.