Sniper Country Duty Roster collective wisdom


Ammunition - Fed 175gr. Match ammo:


Wind Formula. Fed 175gr. Match ammo.

In the U.S. Army manual TC 23-14 Page 3-15, it states;

" The constant for the M118 special ball round is 20. This constant may not remain correct if other ammunition is used. "

If the Federal 175gr. match ammo is used, can someone tell me what the constant # would be for this round in the wind formula?
What would be the constant # be if the Fed. 168gr. match round?

Considering that the Fed. ammo was being shot from the same sniper weapon. (M-24 SWS)

D. West
USA - Tuesday, February 23, 1999 at 03:06:27 (ZULU) 


D West - On the wind formula constant watch out. With a constant of 20 you are getting the answer in half minutes. The TC 23-14 is way out of date get hold of a FM 23-10.

For 100-500 yards use 15, 600 use 1114, 700-800 use 13, 900 use 12 and 1000 use 11. Constants are for M118 SB. Hate to say this but its "close enough" for the others. The wind formula is a SWAG anyway.

I prefer to use a method borrowed from the brits where you look at a wind chart for your specific round and find a velocity where the round is deflected about 1 moa per 100 yards (1 moa at 100, 5 moa at 500, 10 moa at 1000). WIth the M118, a 10 mph wind fits the bill, according to my USMC wind chart anyway. So all I have to do is to determine the velocity then work off of the 10 mph base windage. Example 5 mph at 500 yards is 2.5 minutes of wind because a 10 mph wind is worth 5 minutes. 15 mph at 1000 yards is 15 minutes, 3 mph at 100 is 1/4 moa. On and on.

If you have a ballistics program you can figure out a specific rounds base wind velocity (bullet deflected 1 moa/hundred yards/meters) and amaze your friends and family as you memorize your wind chart.

I find that I am usually within .5 moa of my wind chart when using this method. Wind charts are a SWAG 90% of the time anyway. Learn to read mirage too. It will help you pick up the other components of a given wind situation.

Semper Fi Gunny.
gooch <gooch@stormmountain.com>
Elk Garden, WV, USA - Tuesday, February 23, 1999 at 14:44:41 (ZULU) 


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