Archived | Firearms Examiner Training | Base Construction

Base Construction

Base construction is a feature relating to all types of both plain lead and jacketed bullets.

Examples include the following:

Gas check bullet - composed of a lead bullet with a shallow copper alloy cup fitted to the base

Solid base bullet Courtesy of Ronnie Freels (see reuse policy).	Open base Courtesy of Ronnie Freels (see reuse policy).
Jacketed solid base Courtesy of Ronnie Freels (see reuse policy).	Gas check Courtesy of Ronnie Freels (see reuse policy).

There are many systems for describing the geometry of the base of bullets; the most common variations include these:

More information regarding base shape can be found in the FBIs General Rifling Characteristics database.

Flat base National Institute of Justice (NIJ) (see reuse policy).		Remington bullet heel National Institute of Justice (NIJ) (see reuse policy).
Concave recessed base National Institute of Justice (NIJ) (see reuse policy).	Parabolic concave recessed base National Institute of Justice (NIJ) (see reuse policy).	Conical concave recessed base National Institute of Justice (NIJ) (see reuse policy).
Convex recessed base National Institute of Justice (NIJ) (see reuse policy).		Truncated base National Institute of Justice (NIJ) (see reuse policy).

Date Created: July 12, 2023