An enlargement of the cartridge case head diameter on firing.
Cartridge (firearms) - Wikipedia
Brass Case Shoulder Sizes
7mm PRC (Precision Rifle Cartridge) SAAMI Specs ReleasedThe
L.E. WILSON, INC. L.E. WILSON 22 HORNET CASE GAGE - Brownells UK
Bad Brass or too hot?
Rifle Brass Lifespan - East Coast Reloading Supplies, Inc.
Handloading the 6.5x47 Lapua
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