Resizing
Step 5 of 10 · Return the case to the right dimensions for your chamber.
Firing expands the case to fit your chamber. Resizing brings it back so it chambers reliably and holds the bullet with consistent tension.
Full-length sizing works the whole case body and is the safe default, especially for semi-automatic and field rifles. Neck sizing only works the neck and is common in some precision disciplines. Bushing dies let you choose neck tension precisely.
Measure shoulder position with a comparator and set your die to bump the shoulder back a small, consistent amount, commonly 0.001 to 0.002 inch for a bolt gun. Use case lube as directed by your die maker. Stuck cases are the classic result of too little lube.
← Step 4: Annealing | Step 6: Trimming and Case Prep →
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