Getting a streamer to drop straight down instead of swinging depends on three key factors: line density, leader setup, and initial fly movement. Here’s how to dial it in:

• Use a shorter leader: Long leaders allow the fly to drift and swing before it sinks. Keep it 3-4 feet max to ensure a faster drop.
• Go with a full-sink line instead of a sink tip: Sink-tip lines create a belly that pulls the fly sideways. A full-sink line (Type 5-7 sink rate) keeps the entire system sinking together.
• Pause after the cast: Instead of stripping immediately, give the fly time to free-fall before engaging the retrieve. If you start stripping too soon, you pull it out of the drop zone.
• Add more weight to the fly itself: If your fly is too buoyant, even a sinking line won’t help much. Flies with dumbbell eyes, coneheads, or lead wraps sink head-first and cut through the water column faster.
• Cast beyond the target and let the current help: If possible, cast slightly upstream or perpendicular to the target and let the natural pull of the current sink the fly deeper before starting your retrieve.

Final Thought

If your fly isn’t getting down fast enough, the problem isn’t just the sink rate of the line—it’s how your leader and fly interact with the water column. Make small adjustments to leader length, pause time, and weight to achieve the steepest descent possible.