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Precision Rifle? Or just "Close Enough?"


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What's 1/2 MoA at 20 miles?

 

Found on FB:

 

The 16-inch/50 caliber Mark 7 used on the USS Iowa-class battleships were remarkable for their size and power. These barrels were 50 calibers long, meaning each barrel was 50 times the 16-inch (406 mm) bore diameter, resulting in a total length of 66.7 feet (20.3 meters) from chamber to muzzle. Each weighing approximately 239,000 pounds (108 metric tons) without the breech and 267,900 pounds (121.5 metric tons) with the breech attached.

Capable of firing a variety of projectiles, ranging in weight from 1,900 to 2,700 pounds (860 to 1,220 kilograms). The muzzle velocity of these projectiles varied, but when firing armor-piercing shells, it reached 2,500 feet per second (760 meters per second), allowing for a maximum range of up to 24 miles (39 kilometers). At this maximum range, the projectile would spend nearly 1.5 minutes in flight.

Operating each turret required a crew of 79 men, highlighting the complexity and manpower needed for these formidable weapons. The turrets themselves were a significant investment, costing $1.4 million each, not including the cost of the guns. These powerful guns were a key component of the battleships' firepower, providing unparalleled naval artillery support.

 

FB_IMG_1722790537492.jpg.00e0671048d2e9f5c1f6df91e9b8c327.jpg

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SO!!  It can fire a round that weighs 135,000 times what I shoot from my 1860 Colt replica revolver and it sends it down range at over three times the velocity, not to mention that the projectile travels approximately 42 times the distance that my little round ball would likely go.

 

Kinda’ impressive, don’t ya’ think??

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In the days before precision-guided weapons, U.S. naval gunfire was legendary in its accuracy. It wasn't just the 16-inch naval rifles, but even destroyers that were capable of dropping rounds into a picklebarrrel. The reputation was such that in Korea, an infantry outfit was in some trouble with either North Korean or Chinese troops. The position was near the coast. A U.S. navy destroyer was visible offshore. An American lieutenant called out to the enemy troops that they must surrender, or he would call in fire from the DD. They threw down their arms and surrendered.  It turned out that the LT did not have any radio contact with the destroyer! But the enemy knew the accuracy of naval gunfire would have resulted in certain death! :o

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Posted (edited)
39 minutes ago, Trailrider #896 said:

In the days before precision-guided weapons, U.S. naval gunfire was legendary in its accuracy. It wasn't just the 16-inch naval rifles, but even destroyers that were capable of dropping rounds into a picklebarrrel. The reputation was such that in Korea, an infantry outfit was in some trouble with either North Korean or Chinese troops. The position was near the coast. A U.S. navy destroyer was visible offshore. An American lieutenant called out to the enemy troops that they must surrender, or he would call in fire from the DD. They threw down their arms and surrendered.  It turned out that the LT did not have any radio contact with the destroyer! But the enemy knew the accuracy of naval gunfire would have resulted in certain death! :o

 

It was the USS Wisconsin (BB-64) that obliterated that battery. 

 

https://navalhistoria.com/temper-temper-wisconsin/

 

It was USS Buck (DD-761) that signaled, "Temper,  Temper,  Wisconsin" to Big Whiskey. 

 

There was a thread about it just a few days ago. 

Edited by Subdeacon Joe
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3 hours ago, Texas Maverick said:

Wonder what kind of lead splatter it is gonna make. LOL

 

TM

Enough to make a bunch round balls for Blackwater 

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11 minutes ago, Wyatt Earp SASS#1628L said:

How many pounds of blackpowder per round?


660 pounds of powder!

 

That’s 4,620,000 grains!

 

That’s 154,000 rounds out of my 1860 Colt replica.

 

If I shot as frequently and as much as I did during my most active years, it would take me fifteen and a half years to shoot up one charge used for a 16” gun! :FlagAm:

 

 

Edited by Blackwater 53393
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5 hours ago, Subdeacon Joe said:

What's 1/2 MoA at 20 miles?

 

Found on FB:

 

The 16-inch/50 caliber Mark 7 used on the USS Iowa-class battleships were remarkable for their size and power. These barrels were 50 calibers long, meaning each barrel was 50 times the 16-inch (406 mm) bore diameter, resulting in a total length of 66.7 feet (20.3 meters) from chamber to muzzle. Each weighing approximately 239,000 pounds (108 metric tons) without the breech and 267,900 pounds (121.5 metric tons) with the breech attached.

Capable of firing a variety of projectiles, ranging in weight from 1,900 to 2,700 pounds (860 to 1,220 kilograms). The muzzle velocity of these projectiles varied, but when firing armor-piercing shells, it reached 2,500 feet per second (760 meters per second), allowing for a maximum range of up to 24 miles (39 kilometers). At this maximum range, the projectile would spend nearly 1.5 minutes in flight.

Operating each turret required a crew of 79 men, highlighting the complexity and manpower needed for these formidable weapons. The turrets themselves were a significant investment, costing $1.4 million each, not including the cost of the guns. These powerful guns were a key component of the battleships' firepower, providing unparalleled naval artillery support.

 

FB_IMG_1722790537492.jpg.00e0671048d2e9f5c1f6df91e9b8c327.jpg

 

I'll let you do the math, but it was probably better than 1/2 MOA

 

WWII:  The USS New Jersey & USS Iowa chase the destroyer IJN Nowaki which was damaged by splinters:  https://www.navalgazing.net/Iowa-Part-2

I'll note that the IJN Nowaki was 35' 5" wide.

 

As refitted: As modernized in the 1980s, each turret carried a DR-810 radar that measured the muzzle velocity of each gun, which made it easier to predict the velocity of succeeding shots. Together with the Mark 160 FCS and better propellant consistency, these improvements made these weapons into the most accurate battleship-caliber guns ever made. For example, during test shoots off Crete in 1987, fifteen shells were fired from 34,000 yards (31,900 m), five from the right gun of each turret. The pattern size was 220 yards (200 m), 0.64% of the total range. 14 out of the 15 landed within 250 yards (230 m) of the center of the pattern and 8 were within 150 yards (140 m). Shell-to-shell dispersion was 123 yards (112 m), 0.36% of total range.    http://www.navweaps.com/Weapons/WNUS_16-50_mk7.php

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17 minutes ago, Blackwater 53393 said:


660 pounds of powder!

 

That’s 4,620,000 grains!

 

That’s 154,000 rounds out of my 1860 Colt replica.

 

If I shot as frequently and as much as I did during my most active years, it would take me fifteen and a half years to shoot up one charge used for a 16” gun! :FlagAm:

 

 

 

Sorry, that's not accurate.  Some blackpowder was used on the base of the bagged powder charges as an igniter, but the main charge was not BP:

 

The D839 propellant grain used for full charges originally issued for this gun was 2 inches long (5.08 cm), 1 inch in diameter (2.54 cm) and had seven perforations, each 0.060 inches (0.152 cm) in diameter with a web thickness range of 0.193 to 0.197 inches (0.490 to 0.500 cm) between the perforations and the grain diameter. Each Full Charge D839 powder bag had a 0.79 lbs. (0.36 kg) black powder bag igniter (primer patch).

 

http://www.navweaps.com/Weapons/WNUS_16-50_mk7.php

 

 

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3 hours ago, Red Gauntlet , SASS 60619 said:

I've been curious about the accuracy (as to which I'm ignorant). Why were they not able to put shells directly into the pillboxes at the Normandy invasion? Or were they?

 

The three American battleships at Normandy were the USS Arkansas, USS Texas and USS New York, the oldest battleships in the fleet.  While modernized to a degree, their fire control wasn't as update as the the modern fast battleships.

 

Having said all that, the naval gunfire support of the USS Arkansas, USS Texas and USS New York was quite good and effective.  Naval guns are subject to the same things as any rifle or handgun.  Even minor variations in powder charge, projectile weight, temperature, etc will cause dispersion of shell hits.  Add that a ship is moving in 3 dimensions.  It's a tribute to the analog fire control computers and the quality of the naval guns to get the accuracy that they did.

 

Here is a link for more on the overall subject: http://www.navweaps.com/

 

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Nevertheless!  It takes as much Black Powder as I would use in a typical weekend just to fire the actual charge!!

 

AND! The charge of smokeless would be the equivalent of what a dedicated shooter would use in twenty or thirty years!!

 

That’s a dedicated shooter shooting 36 big matches plus two rounds of all the side matches a year and a ton of rounds in practice  every year!

 

Just a rough estimate…

 

 

 

Edited by Blackwater 53393
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