Understanding the Impact of Transonic Speed on .22 Precision Shooting

I had this topic stuck on my mind after a recent range day with my friends, here are my thoughts. When it comes to precision shooting with a .22 caliber firearm, choosing between subsonic and supersonic ammunition is a key factor. While supersonic rounds offer a flatter trajectory and higher velocity, subsonic ammo has distinct advantages that make it more effective for long-range shooting.

Wind Deflection: The Subsonic Advantage

One of the major benefits of subsonic ammo is its resistance to wind deflection. Supersonic rounds, as they slow down to subsonic speeds, encounter the "transonic effect," where the shock wave created by the bullet’s passage through the air shifts from the nose to the base. During this transition, the bullet experiences precession, where the base stays on its flight path, but the nose spirals around it. This spiraling motion presents a larger frontal surface to the air, increasing wind resistance. As a result, any air movement has a more significant impact on the bullet's point of impact. In contrast, subsonic rounds avoid this issue entirely, experiencing 37% less wind deflection and maintaining a more stable flight path.

Trajectory and Bullet Stability

While subsonic ammo has a more pronounced arc in its trajectory, this can actually be advantageous for long-range shooting. The bullet's flight is consistent and predictable, without the disruption caused by transitioning through the transonic zone. Shooters can more easily account for the bullet drop, knowing the round will remain stable throughout its flight. Supersonic bullets, though initially flatter in trajectory, become less predictable as they slow down and transition through the turbulent transonic phase.

The Case for Subsonic at Range

Subsonic rounds may not travel as fast, but they offer greater long-range accuracy due to their stability. The absence of the transonic effect reduces wind deflection and eliminates the risk of bullet precession, making it easier to consistently hit distant targets. While supersonic rounds excel at shorter ranges, subsonic ammo is the better choice for those seeking reliable accuracy at long distances.