Connection Guide · Electrical

Female Bullet Electrical Terminal

Female half of a bullet (round pin-and-socket) crimp terminal: a tubular split-spring socket, crimped onto a wire and covered by a vinyl or nylon sleeve, that a cylindrical male bullet pushes into.

Illustration of a Female Bullet Electrical Terminal
Gender
female
Connects by
crimp, insertion, friction
Regions
worldwide, North America

How it connects

Wire is crimped into the barrel; the male bullet is pushed into the spring socket and held by friction/spring tension. The insulating sleeve covers the socket mouth so the joint is shielded; not sealed against water.

Male and female halves

This is the female (socket/receptacle) half; the male half is a solid round pin with a bulged tip. Insulated female sleeves cover the whole socket.

Usually connects to

  • Male bullet terminal of matching nominal diameter, commonly 0.156 in (5/32 in, about 4 mm)

Common sizes

  • Common bullets: 0.156 in (5/32 in, about 3.9–4 mm), 0.180 in and 0.187 in; metric versions include 2.8, 3.5, 3.9/4.0 and 5 mm.
  • Wire color codes: red 22–18 AWG, blue 16–14 AWG, yellow 12–10 AWG.

Where it is used

automotive wiring; motorcycle wiringcar audiomarine and RV wiringappliance and lighting wiringLED lighting; trailer lightinggeneral low-voltage DC wiringmarine electricalRC models

Variations

  • vinyl (PVC) insulated
  • nylon insulated
  • heat-shrink insulated
  • double-crimp
  • fully insulated vs partially insulated
  • non-insulated open barrel

How to recognise it

Short colour-coded plastic tube (red/blue/yellow) with a round hole at one end showing a metal tube socket and a wire entry at the other; typically ~6 mm OD, ~20-25 mm long.

Often confused with

Confused withHow to tell them apart
Female spade / quick-disconnect (Faston) terminalSpade receptacles take a flat blade with a rectangular opening; bullet sockets have a round opening. Faston receptacles accept a flat blade tab and have a flat rolled-over opening; bullet sockets have a round opening for a round pin.
Butt splice connectorA butt splice is a permanent crimp on both ends with no socket; a bullet female has one crimp barrel and an open round socket. A butt splice is a permanent tube crimped on both ends; a bullet socket has one crimp barrel and an open socket end.
Hobby RC bullet (gold) connectorsRC bullets (2-8 mm) are usually soldered and uninsulated with slotted male pins; crimp bullets have colour-coded sleeves.
RC hobby gold bullet (2/3.5/4/5.5 mm) connectorsRC bullets are solder-cup, gold-plated, slotted pins without crimp barrels or color-coded sleeves.

Also called

female bullet terminalbullet splice (female half)female snap plug terminalfemale quick-disconnect bullet

Good to know

Bullet sizes are not tightly standardized; 0.156 in is most common in US automotive kits, but 0.180 in and 3.5/4 mm exist and do not intermate. Sample part (Gardner Bender 15-163P) is 0.156 in, 16-14 AWG.

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