July-August - Air Defense Artillery School

1';J-fj
COAST ARTILLERY BOARD A'OTES
problem and such remedial action as may be practicable
will be taken. The Commanding General, Army Ground
Forces. has approved the Board's recommendation.
Subcaliber GullS. The Ordnance Department has under
de\'elopment 75mm subcaliber guns for all modern seacoast
, fixed and railwa)' artillerv- of 6-inch caliber and above.
These subcaliber guns are to be delivered for test during
July and August. It is expected that production will fol-
Io\\' test shortly. The guns for 16-inch batteries are to be
issued first. All of these guns are in the form of tubes to
be inserted in the chamber. The ammunition to be used
\\ith these guns is the 75mm Shell, ~148, inert loaded and
with ignition primers. Normal charge only is provided.
Thus the standard firing circuit and breech block are used
\rhen firing the subcaliber, and the training of the gun
crew will more nearlv simulate actual service conditions.
A 37mm subcalibe~ gun is under development for use
Irith the 90mm Gun on Fixed ~Iount. This gun is in the
form of a tube also. The ammunition to be used with this
gun has not been specified to date.
I Coast Artillery Memorandums. Coast Artillery ~Iemorandum
No. 22, 1 June 1942, covers thoroughly all im-
, portant features arising in 1941 target practices. Due to the
I relatively higher importance of other reports and tests, a
Coast Artillery memorandum covering the target practices
fired during the calendar year 1942 will not be published.
I
The principles discussed in Memorandum No. 22 are as
appropriate as they would be if based on 1942 practices,
and this memorandum should be continued in use as a cur-
I rent guide. The results of the 1942 practices, it is expected,
I will be combined with those of 1943 reports in a memo-
, randum to be published in 1944.
"\Farm-up Effect"-90mm GUllS. Limited experience in
firing 90mm guns on the fixed mount indicates that a
I "wann-up" effect exists with these guns comparable to that
I frcquently found with 3-inch seacoast guns. Data to date
! point to the fact that the so-called "warm-up" effect is really
a "clean gun" effect. In other words, the excessively short
I dcviations occur on the first rounds fired from clean ouns
o
I onl".
57
be published shortly. Forms may be obtained from the
Coast Artillery Board. T~ I II --B4 covers the description
and operation of the spotting set. Due to the time factor
and the nature of the data required, coordinated training
of the personnel involved in record taking is of great importance.
Alllm llIlition Allowances. Pending the publication of
appropriate changes in AR 775-10 dated 13 ~Iarch 1943.
the \Var Department has granted authority for the expenditure
of additional Coast Artillery ammunition. Eight-inch
railway gun batteries are authorized a total annual allowance
of fifty-six rounds and 16-inch gun batteries are authorized
an allowance of twenty-eight rounds. The increased
allowance for railway units was made to permit the
firing of four guns.
Drill Plugs for 15511I11/ GIIIl Materiel. The following
information, from \\leekly Directive No. 19, Headquarters
Arn1Y Ground Forces, will be of interest to 155mm gun
battery commanders. ~ lany 155mm gun batteries are not
equipped with brass dummy plugs to replace firing pin
housing, firing pin, and firing pin spring, during gun drill.
Failure to employ this dummy plug results in excessive
wear on percussion hammer and firing pin. Plug, drill,
A 130622 is listed on page 121, of Standard Nomenclature
List D30, Gun 155mm, M1917 andl\l1918 Ml; and Carriage,
Gun, 155mm, l'v11917Al, M2, M1918Al, and M3,
10 October 1942. The basis of issue of this item during
peacetime for drill purposes only is one per gun. It is
listed in Standard Nomenclature List D-24, Gun, 155mm,
1\11 and ~IIAI and Carriage, Gun, 155mm, Ml, on page
104. It may be requisitioned on this basis for 155mm
Guns, Ml and MIA1.
Sights mId Sight lHOH1lts for 12- mId 16-inch CtrSemated
Batteries. The Coast Artillery Board has recommended that
sights and sight mounts not be furnished for those 12-inch
and 16-inch casemated batteries so sited as to preclude Case
II fire, and that the shields for batteries so sited not be provided
with sighting apertures. The Board has recommended
also that those 12-inch and 16-inch batteries already
installed, so sited as to preclude Case II fire, have the
It is suggested that particular attention be paid, when
sights removed and apertures in the shields closed.
• firing the 90mm gun on the fixed mount at waterborne tar-
The Commanding General, Army Ground Forces, has
gets,to determining whether or not a clean-gun effect exists.
approved these recommendations and has recommended
-\ssuming a clean-gun effect, the solution is to disregard
that the necessary ::.':t;on be taken to put them into effect.
I the first salvo fired if it is short. If the first salvo is over an
DUll/my Clwrge Extractor M 1911. The dummy powder
adjustment of down one fork should be made and thereafter
charges used for drill on all moclels of 6-inch guns are single
the first salvo should be disregarded.
section and can be removed more easily from the chamber
Training equipment. At the present time, most harbor
without the use of a dummy charge extractor. The dummy
defenses are authorized one Spotting Set PH-32 or
charge extractor has no other use in these batteries. The
PH-32-B. The next published change in Table of Basic
Chief of Ordnance has changed the lists of tools and acces-
Allowances No.4 will authorize the issue of this set to all sories for all types of 6-inch batteries to eliminate the
Iharbor defenses.
Dummy Charge Extractor M1911.
When firing rapid fire armament, the determination of
Improved Means of !\'leasuring Powder Temperatures.
• aCcurate deviations is practically impossible using the
Action has been initiated to provide seacoast artillery bat-
CUstomarymethod of observing lateral deviations from the
teries with Powder Temperature Thermometers Ml or
licinity of the battery and photographing each splash from
Powder Temperature Indicators M 12 or M 13, whichever is
thetowing vessel. The two-station camera spotting unit has
applicable to the particular battery. These thermometers
been used successfully to determine the lateral and range
and indicators provide improved means for determining
deViationsof each splash when firing the 3-inch and 90mm
the temperature of powder charges in that the temperature
batteries. The method of computing data and forms to be inside the charge is indicated.
usedwill be covered in a chanoe to T~I 4-235 which should
o
The recommended basis of issue is two Powder T empera-