From: research66@MKTSurvey.net
Date: Mon Dec 09 2002 - 15:19:27 PST
Everette:
HOOD's main battery of eight 15 in 42 caliber guns meant that each gun was
indeed 15 inches in diameter and the length of the barrel was 42 times the
diameter. Same for the secondary battery of 5 in 50 cal, those guns were 50
times the diameter in length. Germany's BISMARK had eight 15 in 47 cal
guns, slightly improved over HOOD, but not much. Britain's last and most
modern battleship, VANGUARD, had the same eight 15 in 42 caliber guns that
HOOD did. VANGUARD was scrapped in 1961.
You may not think this makes any difference in the guns, but in U.S.
battleships, the NORTH CAROLINA and SOUTH DAKOTA-classes had nine 16 in 45
cal guns, each gun barrel was 45 times the width (16 inches) = 720 inches
long; the follow-on IOWAs had nine 16 inch 50 cal guns, three calibers
longer which came out to 800 inches long. The difference in performance of
the two guns was that NORTH CAROLINA and SOUTH DAKOTA-class ships 16 in guns
range was 20 miles and were more deadly in plunging fire (higher angle) and
IOWA-class ships 16 in 50 cal guns had a range of 23 miles (both shot same
shell, same powder bags) and was more devastating at longer range, lower
trajectory.
The extra length of the barrel, measured in calibers, gives the guns higher
muzzle velocity (greater speed of the round) and also puts more spin on the
round because it is in the barrel longer, and being spun by the rifled
grooves for a longer period of time with the expanding gas behind it.
R. S. Rayfield, Jr.
Maj USMC (Ret)
-----Original Message-----
From: Everette [mailto:194cbteng@pchnet.com]
Sent: Monday, December 09, 2002 6:02 PM
To: mil-veh@mil-veh.org
Subject: [MV] dia. and caliber
This is description of HMS Hoods main battery - would someone explain in
terms an old country boy can understand what makes a gun a 15 inch, 42
caliber -- it has been my understanding that the 15 inch referred to dia. of
inside bore, am I correct in this understanding?? What does 42 caliber mean
same for 5.5 inch 50 caliber
Guns:
8-15 inch. 42 cal.
12-5.5 inch. 50 cal.
Thanks
Everette
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