Physical Features

Most modern bullets fall into two categories:

• Plain lead bullets ( swaged or cast)
• Jacketed bullets (heavy core enclosed by an outer jacket of gilding meta(heavy core enclosed by an outer jacket of gliding metal)

Within these two categories, there are a wide variety of bullet designs intended to improve performance for a particular purpose.

 

 

 

Terminology

Common Terms
Term	Definition
Bullet	Nonspherical projectile for use in a rifled gun barrel
Tip	Extreme forward end of a bullet
Meplat	Blunt tip of some bullets, specifically the diameter of that blunt tip
Ogive	Curved forward part of a bullet
Nose	Forward end of a bullet, including the tip, the ogive, and meplat (if present)
Cannelure	Circumferential groove in a bullet generally of a knurled or plain appearance for the purpose of lubrication or identification, or to assist in crimping a bullet in the mouth of a cartridge case
Bearing surface	Portion of the outer surface of a bullet that makes direct contact with the interior surface of a gun barrel
Base	Rear portion of a bullet
Heel	Configuration of the intersection of the bearing surface and base of a bullet

 

Characteristics

The categories of physical features of bullets are extensive and can be used to search reference materials for bullets with similar features.

The primary physical features of bullets include these:

• Weight
• Measured caliber/diameter
• Composition
• Jacket type
• Magnetic properties
• Length
• Color/finish
• Base construction
• Base shape
• Nose construction
• Nose shape
• Cannelures

Weight

The weight of a bullet is normally measured in grains using a balance. There are 7000 grains per pound or 437.5 grains per ounce.

The weight of a relatively intact bullet is a partial indicator of the type(s) of cartridge that may have contained the bullet. Weight is one of the factors used to determine cartridge type(s).

In the following chart, the weight of a bullet in grains corresponds to possible cartridge type(s). A bullet weight may overlap several cartridge types, indicating that more data are needed to narrow the field.

Range of Bullet Weights for Various Cartridge Types
CARTRIDGE	WEIGHT RANGE (grains)
17 Remington	25
22 Short	27-30
22 Long Rifle	36-40
22 Win Mag	30-50
25 ACP	45-50
7.62 Tokarev	84-92
7.65 (30 Luger)	90-96
32 S&W	85-88
32-20 WCF	90-115
32 Short Colt	80
32 Long Colt	82
32 S&W & 32 S&W Long	95-100
32 Auto	60-71
8mm Nambu	99-103
380 Auto	85-102
9mm Parabellum	88-147
9mm Makarov	90
9mm Steyr	114-118
9mm Mauser	123-128
38 S&W	145-150
38 Long Colt/Colt New Police	148-150
38 Special	95-158
357 Magnum	110-180
38 Auto	115-147
40 S&W	141-180
10mm Auto	155-200
41 Rem Magnum	170-240
41 Short Colt	160-167
44 Rem Magnum	180-275
44 S&W Spl	200-246
45 ACP	175-230
45 Colt	225-255
Popular small caliber excluding reloads Sources: Hatcher, H.P.White Lab, CCI, Winchester, Remington, Federal

 

Considerations

When obtaining the remaining weight of a fired evidence bullet, the examiner should bear in mind the following considerations:

• Laboratory safety protocols should be followed.
• Laboratory trace evidence policies should be followed prior to and during removal of any material adhering to a bullet.
• Bullets should be cleaned so as to not damage the surfaces potentially bearing microscopic marks.
  • Soak in a mild detergent to loosen any adhering material. Gently scrub using a soft bristled toothbrush.
    
    -and/or-
    • Use an ultrasonic cleaner and appropriate fluid.
      • Follow the manufacturers recommendations.
      • Treat one bullet/fragment at a time.
      • Monitor and observe bullets during treatment; ultrasonic cleaning may alter the microscopic details on the surface of a bullet.
    • Use appropriate tools to mechanically remove debris (e.g., embedded wood particles, bone, cartilage).
• Weigh each bullet fragment separately because they may or may not originate from a single bullet. Individually weighed fragments can be regrouped later, if necessary.

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