Posted by L.E. Wilson INC. on 3/17/2025 to
Bullet Seating Dies
For precision shooters and reloaders, every step of the reloading process affects accuracy. One of the most critical steps is bullet seating—the process of inserting a bullet into a prepared case to achieve the correct depth and alignment. Whether you're reloading for competition, hunting, or general shooting, understanding bullet seating is essential for consistent performance and safe chambering.
What Is Bullet Seating and Why Does It Matter?
Bullet seating refers to the process of pressing a bullet into a brass case to a specified depth, ensuring consistent cartridge overall length (COAL) and proper chamber fit. Incorrect bullet seating can lead to:
- Inconsistent Accuracy – Variations in seating depth affect pressure and velocity.
- Chambering Issues – If a bullet is seated too deep or too shallow, it may not feed properly.
- Over-Pressure Conditions – Seating too deep can increase pressure, leading to dangerous conditions.
Key Factors in Bullet Seating
1. Cartridge Overall Length (COAL)
The COAL is the total length of the loaded round from base to bullet tip. A consistent COAL ensures proper feeding and chamber fit while maintaining safe pressure levels. Each caliber and firearm may require a different optimal COAL for best performance.
It’s also important to understand OAL (Overall Length) — which refers to the distance from the head of the case to the bullet’s ogive (the curved part that engages the rifling). Measuring both COAL and OAL helps reloaders precisely control seating depth, especially when tuning loads for accuracy. While COAL is standard for most manual measurements, OAL provides a more precise reference point for how the bullet aligns with the barrel’s rifling.
2. Bullet Depth and Engagement
Seating depth affects how the bullet interacts with the rifling in the barrel. A bullet seated too far off the lands (the start of the rifling) may decrease accuracy, while one seated too close could increase pressure and could also cause inconsistent accuracy. Precision reloaders often adjust seating depth off the lands to fine-tune accuracy.
3. Neck Tension
Proper neck tension keeps the bullet securely in place, preventing movement during feeding and firing. Using a high-quality bullet seating die ensures consistent and repeatable neck tension, improving shot-to-shot uniformity.
How to Seat a Bullet Correctly
- Prepare Your Brass – Ensure the case is trimmed, deburred, and properly resized.
- Set the Bullet Seating Die – Adjust the L.E. Wilson Bullet Seating Die to achieve desired correct COAL or OAL.
- Seat the Bullet – Slowly press the bullet into the case using a precision inline seating die.
- Measure COAL and OAL – Use calipers for COAL, or calipers in conjunction with a bullet comparator kit for OAL, to check consistency and adjust seating depth if needed.
Precision Tools for Bullet Seating
Using a high-quality bullet seater is essential for achieving consistent and accurate results. L.E. Wilson Bullet Seaters are known for:
- Inline Seating Design – Simulates chamber fit for uniform alignment.
- Micrometer Adjustments – Allows for precise depth control.
- Consistent Seating Depth – Because there are no threads on the Bullet Seating Die, we count on the die body to produce consistent, repeatable results, which enhances accuracy.
- Full Bullet to Case Alignment – Bullet aligns fully with case prior to the seating operation.
- Definite Stop – The bullet seater cap bottoms out on the die, creating a very consistent COAL and OAL on every round.
Final Thoughts – The Importance of Bullet Seating
Proper bullet seating is essential for accuracy, safety, and reliability in reloaded ammunition. By fine-tuning seating depth, COAL, and neck tension, reloaders can achieve repeatable, match-grade performance.
Want to improve your bullet seating process? Check out the L.E. Wilson Bullet Seaters to take your reloading precision to the next level!