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Old 05-16-2007, 14:28   #4
Go For Broke
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Join Date: Apr 2005
Location: HI
Posts: 242
I have not heard of it for the mortars, but as an old 13 series, that was one of the variables we had to account for during manual cannon gunnery (which failed many a young 2LT)

From the Now FM 6-40 (Formerly TC 6-40)
Quote:
(1) Range effects Some of the deviation from standard conditions affecting range are: Muzzle velocity. Projectile Weight. Range wind. Air temperature. Air density. Rotation of the earth
(Para 3-3 Exterior Ballistics, 3, (1))

This Rotation of the Earth was used during computation of Safety and during METerological Data Corrections for a firing solution. Correction factors applied to Range (in meters) was Table H in the Tabular Firing Tables and Correction factors applied for Azimuth (in mils) was Table I for the TFTs. This information was based off of 0 degrees latitude, with additional modifiers based of distance from 0 degrees latitude. FYI - These TFTs are rather thick, with different information for various weights of projectiles, types of projectiles, and type of projectile launcher (105mm or 155mm (current))

This is in addition to all the other factors that were taken in during the computation of safety / firing solutions which included such things as ambient temperature, tube temperature, powder temperature, winds, tube wear, projectile weight, high angle or low angle fire, elevation, displacement from base piece, time of flight, muzzle velocity variations, etc...etc...to include how much copper was deposited on the lands and grooves of the tube

Pete hit it on the head, when he said that
Quote:
You would have to compute where you were {are} and what direction you were shooting {target location}
for it to be really effective.

Just my humble $0.02

V/R,
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