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Charge planning

Case Fill Calculator

Estimate fill percentage, compression risk, and headroom so you can choose safe charge weights and seating depths.

The weight in grains of water a fired, unsized case holds when filled level with the case mouth. Use a measured average for your brass lot when possible.

Use your measured water capacity or manual data for the cartridge.

The exact powder mass planned for one cartridge. Use only a charge supported by current published load data.

The specific charge weight you plan to load.

Target fill range (%)Optional lower and upper fill percentages used only to flag results. These limits do not establish whether a load is pressure-safe.
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Optional guardrails to highlight underfilled or compressed loads.

How far above 100% fill the estimate may go before the result is flagged as compressed. This is a planning tolerance, not a safe-charge allowance.

Adds a tolerance before flagging a load as compressed. Default is 3%.

Fill percentageEstimated powder charge divided by water case capacity. Powder bulk density varies, so verify actual fill with the exact powder and brass. —
HeadroomCase water capacity minus powder charge, expressed as a grain-weight comparison. A negative value indicates estimated compression. —
Status —
Notes —

Interpretation

Fill guidance

Use this to catch compressed charges or overly low-fill combinations before heading to the press.

  • Enter your case capacity and charge to view results.