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Let's talk sub-MOA accuracy....

Started by ITB, November 22, 2013, 08:03:38 PM

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ITB

November 22, 2013, 08:03:38 PM


QuoteAnd her two advanced guns on the forward deck can hit a basketball with a 155mm Howitzer-sized artillery shell from 63 miles away.

If my math is correct, the basketball at that distance is 0.0086 MOA.  To put that in perspective, that's like hitting a human hair at 50 yards.

As my wife just said, "Is this the Navy's way of saying they can hit a pirate's head with a 6" shell from 63 miles away?"

Just having fun with MOA and math.

Full article here: http://www.defenseone.com/ideas/2013/11/inside-secret-interior-navys-first-stealth-destroyer/74321/

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SteelThunder

#1
November 22, 2013, 08:19:32 PM
I'm guessing those shells have some guidance on-board
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Rocket Man

#2
November 22, 2013, 08:38:18 PM
Quote from: intheburbs on November 22, 2013, 08:03:38 PM
If my math is correct, the basketball at that distance is 0.0086 MOA.  To put that in perspective, that's like hitting a human hair at 50 yards.

Yep.  Or 2.35 microradians. 

Quote from: SteelThunder on November 22, 2013, 08:19:32 PM
I'm guessing those shells have some guidance on-board

Correct.

Although to put it in perspective, in the old days of battleships with optical gunsights, the required accuracy standard was about 60 feet (roughly the width of the target battleship's belt and deck, as seen by the projectile plunging at an angle) at 18,000 yards -- or 4 MOA.  Provided, that is, the environment cooperated, which it rarely did, and so they shot a lot of sighters.

Apparently "rack grade" applies to naval rifles as well.  :D
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Oz

#3
November 22, 2013, 08:44:27 PM
Does this mean we finally get to include the coriolis effect in IMC?   ;D
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Rocket Man

#4
November 22, 2013, 08:57:46 PM
It's actually cross-range, not Coriolis...   @)  You must have more mathematically inclined students than I do, mine usually start to experience their eyes glazing over before I get to Magnus effect.
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kenjo

#5
November 22, 2013, 09:59:28 PM
Dumb question--why is the navy shooting basketballs?


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mac66

#6
November 22, 2013, 10:07:07 PM
Quote from: kenjo on November 22, 2013, 09:59:28 PM
Dumb question--why is the navy shooting basketballs?



Why indeed?

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Surveyor1653

#7
November 22, 2013, 11:11:42 PM
Quote from: kenjo on November 22, 2013, 09:59:28 PM
Dumb question--why is the navy shooting basketballs?


::)

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Whippet

#8
November 22, 2013, 11:43:00 PM
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jmdavis

#9
November 23, 2013, 11:17:36 PM
The 63 miles is a sticking point for me. 63 miles with a useful payload for infantry support or counter battery is hard to believe. Here is some additional information. The shell ways over 250 lbs, but only carries a 24 lb warhead.



http://www.guns.com/2013/09/23/lockheed-lands-18-million-contract-manufacture-155mm-lrlap-navy/

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Rocket Man

#10
November 24, 2013, 01:08:33 AM Last Edit: November 24, 2013, 02:11:26 AM by Rocket Man
Size of needed payload scales as the third power of CEP...  rather like the difference between a rifleman and a mere musketeer!

The Air Force these days is often resorting to concrete bombs rather than explosives, since they have the accuracy to bulls-eye individual structures.  There is also the Small Diameter Bomb entering service for similar reasons, with a similar amount of explosive to the AGS.

Anyway, things have changed a bit since the rocket's red glare, but not so much that our forefathers wouldn't understand what they were looking at.
... if ever a mistaken complaisance leads them to sacrifice their privileges, or the well-meaning assertors of them, they will deserve bondage, and soon will find themselves in chains. -- Joseph Warren (anon)
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