US Artillery - Ammo & Fuses

US Artillery Fuses and Ammo - Page Title
FUSES & AMMO

 

INTRODUCTION FIRE PATTERNS
TARGETING FIRE DOCTRINE
FIRE SUPPORT BASES OBSERVATION
FIRE TYPES ARTILLERY TO&E'S

FUSES

Quick Fuse
Quick fuse is a contact fuse -- the shell goes off when it touches something hard, like the ground, a tank, or trees.

Mechanical or Powder-Train Timer Fuse
The shell goes off some time after it is fired. Usually, this is timed to give an air burst, which is most effective at about 20 yards above the target. 

VT (Proximity) Fuse
The VT fuse emits a radio signal and goes off when it detects enough of this signal is being reflected back from a hard object. The height of burst will increase if over dense foliage, swamp, water, or wet terrain; and it will decrease with high-angle fire. 

The minimum ranges in yards for several guns is shown below:

Weapon Minimum Range

105mm Howitzer 2,700
155mm Howitzer 4,000
8" Howitzer 6,000

 

Delay Fuse
With the delay fuse, the shell goes off some time after hitting a hard target. This can be used either to penetrate a target before detonation (such as a bunker), sink into the ground a ways before detonation (to produce craters), or to purposefully richochet and produce airburst effects. Richochets occur more frequently with low-angle fire and hard ground. Richochet fire should only be attempted if the observer can verify that at least 50% of the shells are actually richocheting. If not, another type of fuse should be specified.

 


AMMO

High-Explosive (HE)
When a HE shell explodes, most of the fragments shoot out in a circular pattern from the sides of the shell, with some amount of fragments from the nose and tail. Unless the angle-of-impact is very high, the fragments that shoot upwards are ineffective.

HE Burst Area
The burst area in yards for a single HE shell with quick fuse, defined as the area in which there is at least a 50% chance that a standing man will become a casualty, is given below for various guns. Depth is in the direction that the shell is travelling -- due to side-spray, the area is longer along the perpendicular. Large fragments can be thrown over a larger area, as is shown by the last column. Remember that this is the burst area for a single shell, not a volley.

Piece Depth Width Large Fragments

105mm Howitzer 15 50 300
155mm Gun or Howitzer 18 60 550
8" Gun or Howitzer 20 80


White Phosphorous (WP)
WP produces smoke, incendiary effect, and casualties. Quick fuse is preferred in all cases -- unlike HE, with WP, those fragments that shoot upward are actually useful. Because the burning is very hot, smoke tends to pillar upwards rather than spreading across the battlefield. To build a smoke screen, more ammo must be used than conventional smoke shells.

For casualties, WP should be treated as about half as effective as HE, though all shots should be treated as airbursts.

Base-Ejection Smoke
If a smoke shell penetrates the ground or hits it too hard, the smoke effect will be minimal. Base-ejection shells throw the smoke generating part of the shell backwards just before impact so it is moving at a slower velocity when it hits the ground and is unlikely to penetrate.

Most smoke is produced by hexachlorethane (HC), which burns cold, so the smoke will tend to drift along the ground as blown by the wind. Rain makes it more effective. Smoke shells take 30-60 seconds to build a cloud; 1-2 minutes to reach maximum effectiveness; and they burn 3-4 minutes.

If the wind is parallel to the screened front, the shells can be spaced by as much as 400 yards. If perpendicular, they might need to be as close as 30 yards. Ammo expenditure per minute per point in the screen is 1-2 shells for 105mm, depending on the wind, and .5-1 shell for 155mm.

Illuminating Shells
Illuminating shells burn for about a minute. In all cases, it's best to have coverage from at least two shells to minimize shadows. They should burst at about 700 yards of height; be spaced about 700 yards apart; and be fired at a rate of about 2 rounds per minute. A single 155mm shell will illuminate an area about 1000 yards in diameter.

 


Courtesy of Daryl Poe


 

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