No discussion of reloading is complete without a basic understanding of the components that make up a shotshell. The image below is a cross section of a standard shotshell, and the various components are described in brief and labeled accordingly.
A) CRIMP: Seals all components tightly inside the hull. May be 6 or 8 point.
B) HULL: The outer case that holds the components. May be plastic or paper.
C) WAD: Confines powder for uniform ignition and separates powder from shot. (The wad most often used is a one-piece shot cup and wad called a “wad column”.)
D) BASE: Holds primer and securely anchors shell in gun breech. May be brass or steel.
E) PRIMER POCKET: Opening in metal base into which primer is inserted.
F) SHOT: Comes in variety of sizes and types for different shooting situations.
G) SHOT CUP: Plastic cup holds shot in the pattern as it leaves gun muzzle.
H) POWDER CHARGE: When ignited by primer, powder charge, burning at a controlled rate, generates gas pressure which, with the aid of wad column, propels shot out of the gun barrel.
I) PRIMER: Gun firing pin detonates component in primer, which ignites the main powder charge.
Article content and images provided courtesy of Mayville Engineering Company, Inc. (www.mecreloaders.com)