Train
Ladder / OCW Test
advancedFind your rifle's optimal charge weight (OCW) node — the powder charge where groups tighten and velocity spread drops. Requires reloaded ammunition at multiple charges.
Fire each charge weight group at its designated aim point. Record exact POI for each group. The OCW shows as consecutive groups printing at the same POI despite the increasing charge — meaning the bullet is leaving at the same point in the barrel's harmonic cycle.
Prepare 3–5 rounds at each of 5–7 charge weights, in 0.2–0.3gr increments, spanning ±0.5gr around your expected OCW. Label each group. Use a calm-wind day. 100-yard target with separate aim points per charge weight. Cold barrel for first string; let cool between strings.
Identify the charge range where 2–3 consecutive groups share the same vertical POI (within ½"). That range contains your OCW node. Velocity ES/SD from a chronograph (ideally ≤10 fps ES) confirms it. Pass = node identified. Fail = no convergence found (extend ladder, vary seating depth).
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