Bench 6

Seating

Set bullet seating depth precisely and consistently. COAL and jump-to-lands are the variables that connect your load to your rifle's chamber.

← Bench 5 — Powder Bench 7 — Summation →
New to reloading? Start with Basics only. · Already reloading? Use Basics as a refresher, then dig into Control and Tune.
Basics
What you're doing and why
Seating depth determines how far the bullet travels before it engages the rifling. Get your COAL consistent first — then tune from there.
1
Set your seating die

Thread the seating die in until it contacts the case, then back off slightly. Your target is a specific COAL — not "close enough." Set the die, seat a dummy round, measure, and adjust until you're hitting your number.

You'll need Bullet seating die + calipers
2
Seat each bullet to the same depth

Run each case into the die with a smooth, consistent stroke. Inconsistent press speed produces inconsistent seating depth. Measure every round until you trust your setup — then spot-check every tenth.

3
Measure and verify COAL

Cartridge overall length is your primary output from this bench. Measure with calipers from the case head to the bullet tip. Record your average — and flag anything outside ±0.005" of your target.

You'll need Calipers
Control
What you're controlling
COAL is your primary control variable. Measure every tenth round minimum. Seating depth drift is a die maintenance issue — catch it early.
C1
Control Point 1
Cartridge Overall Length (COAL)

Your target COAL comes from load data and your chamber. Record the exact number you're working to. If you're using a magazine-length constraint, document that too — it affects what's achievable.

C2
Control Point 1
Jump-to-Lands

Jump is the distance between the seated bullet's ogive and the rifling. It's chamber-specific — measure yours with a Hornady OAL gauge or equivalent. Document the measurement date; throats erode with round count.

You'll need Hornady OAL gauge or equivalent
Tune
V1 status
Jump-to-lands is the tune variable most reloaders reach for after charge weight. Small changes — 0.010" at a time — produce measurable accuracy shifts in most rifles.
T1
Seating Depth as a Tune Variable

Most rifles have a preferred jump range — typically 0.010" to 0.040" off the lands, though some prefer jammed or near-jammed. Start at your current COAL and work in 0.010" increments. Qual8 maps seating depth against group size and ES so you can see the trend instead of guessing at it.

Logbook Record Layer

- Target COAL and actual average measured
- Jump-to-lands measurement (if taken)
- Die setting used (stem position)
- Any rounds flagged for re-seating
- Bench date and session number

Bench walkthrough
Watch the bench in practice
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Bench 6
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Bullet seating walkthrough — die setup, COAL measurement, and jump-to-lands
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