

MC-40 4wt Fly Line
A perfect blend of precision and power, the MC-404 fly line enables featherlight presentations over long distances.
Description
The tapered head is contained within the first 40ft of this powerful, long distance fly line. Adhering to AFFTA specifications, it contains 120 grains (7.8 grams) in the first 40 ft of line and is designed to enable your rod to cast butter smooth. Designed for an accurate and delicate final presentation, the MC-404 is ideal when fishing for skittish brookies and other small trout in crystal-clear mountain waters. Welded loops at both ends make for efficient loop-to-loop attachment.
Specifications
- Line Size: 4-Weight
- Taper: Taper Contained in First 40 ft
Physical Weight in Grains & Grams
- 4wt: 120.0 grains / 7.80 grams
- 5wt: 140.0 grains / 9.0 grams
- 6wt: 163.0 grains / 10.5 grams
- 7wt: 182.0 grains / 11.8 grams
- 8wt: 204.0 grains / 13.2 grams
- 9wt: 235.5 grains / 15.2 grams
- 10wt: Not Available in 10wt
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Fly Line | MC-30 Fly Line | MC-38 Fly Line | MC-40 Fly Line |
Available Sizes | 4wt - 10wt | 4wt - 9wt | 4wt - 9wt |
Taper | Taper Contained in First 30 ft | Taper Contained in First 38 ft | Taper Contained in First 40 ft |
Physical Weight | --- | --- | --- |
4wt | 149.0 grains / 9.70 grams | 130.0 grains / 8.39 grams | 120 grains / 9.00 grams |
5wt | 173.0 grains / 11.20 grams | 150.0 grains / 10.0 grams | 140.0 grains / 9.0 grams |
6wt | 189.0 grains / 12.30 grams | 171.0 grains / 11.10 grams | 163.0 grains / 10.5 grams |
7wt | 224.0 grains / 14.50 grams | 188.0 grains / 12.2 grams | 182.0 grains / 11.8 grams |
8wt | 245.0 grains / 15.80 grams | 222.0 grains / 14.4 grams | 204.0 grains / 13.2 grams |
9wt | 306.5 grains / 19.80 grams | 306.5 grains / 19.8 grams | 235.5 grains / 15.2 grams |
10wt | 362.5 grains / 23.50 grams | Not available in 10wt | Not Available in 10wt |
Our Favorite Uses | Large nymphs & roll casting | Light nymphs or dry flies; Long casts in med/big waters | Long distance casting, windy conditions |

Montana Casting Co. Fly Lines
Each Montana Casting Company fly fishing line is designed to company founder Scott Joyner’s specifications to take full advantage of your rod’s dynamic power curve. Wind, rain, snow or shine, these lines are precision-engineered and Montana-tested for accurate casting with minimal effort.

Useful Fly Fishing Knots for Attaching Your Fly Line
How to Tie a Perfection Loop
Scott shows you how to tie one of the easier fly fishing knots, the perfection loop. This knot can be used to attach a leader to the end of a fly line that has a welded loop on it. Watch a video demonstrating the Perfection Loop.
How to Tie a Nail Knot
Scott demonstrates using a nail knot tool to attach a length of butt section to a fly line. Watch our Nail Knot Video on YouTube.