There few flies that are developed as general attractor patterns, but happen to really work for a very specific hatch. One of those patterns is Howard Croston’s Full Metal Jacket from our friends over at Fulling Mill for use fishing our spring March Brown hatch. The flies produced by Fulling Mill have an astounding level of consistency, which for this particular hatch is exceptionally important.
March Browns belong to the clinger family of mayflies which means they have a very unique body shape, silhouette, and leg configuration. There is nothing else hatching in our rivers this time of year that looks like a March Brown; in fact, we don’t have too many other major hatches of clinger mayflies aside from our beloved March Brown. Having consistent flies batch to batch is crucial with nymphs with as many unique attributes as March Browns.
Clingers are characterized by their flat, ultra-streamlined bodies which allow them to thrive in areas of the river that other nymphs cannot. Their bodies are wide and their legs are burlier than swimming, burrowing, and crawling mayfly nymphs. March Browns, clinger mayflies broadly speaking, are the masters of adaptation and have filled a niche of the river that at one point was not habitable for larger, clumsy nymphs.
Howard Croston is an English fly angler, fly tier, fly designer for Fulling Mill, and member of the English National Fly Fishing Team. His Full Metal Jacket serves as an attractor pattern, but really excels for our spring March Brown hatch.
The FMJ’s construction really caters to the clinger family of mayflies. A collar of hair holds its shape and provides an extra wide body near the bead, similar to a March Brown nymphs natural taper. The body of the fly is constructed of a biot and provides both realistic texture and segmentation.
I believe I read somewhere that the extra-heavy drop tungsten bead is fixed with solder for additional weight. This is perfect for spring as we can have unpredictable high flows. The FMJ’s slim body cuts through the water, with the collar/legs still providing a wider, tapered silhouette that our trout are currently keyed in on.
I like to fish this fly in tandem with something bigger. Here are some flies I like to fish it in tandem with when the water is high: Bubba’s In The Zone Stonefly Nymph, Olsen’s Straggle Stone, a Slush Egg, Weiss’ Secret Worm, or Croston’s Jigged Chenille Worm. When the water is low and clear, I like to fish smaller, slimmer offerings in tandem with a Full Metal Jacket. Here are some options: Weiss’ Possum Anchor Jig, Olsen’s Blowtorch, Croston’s Spring Brown Jig, or Weiss’ BP Dark Heavyweight Perdigon.
It is worth noting that Croston does have a Spring Brown Jig that is another fantastic option for the March Brown hatch. The beauty of the Full Metal Jacket is that it is versatile and can be fished year round as well. It is a fantastic attractor pattern that can be run under a large gold chubby in the summer, or under an oros indicator in the middle of winter.
– Simon
If you want to tie some, the recipe is listed below. The possibilities are endless with color & size combinations.
Hook- Fulling Mill Jig Force FM5045
Bead- Fulling Mill Tungsten Drop Bead
Thread- Fulling Mill Pro Thread Flat 70D
Tail- CDL
Body- Turkey Biot
Thorax- Fulling Mill Eco Warrior Dub
Legs- Deer Hair
Flash- Flashabou
