US NAVY PAGES
POWDER INDEX OR LOT
NUMBERS AND WEIGHT
BOBC 59 FURNISHES THE ABOVE LIST OF AMMUNITION BB59 RECEIVED FROM AN AMMO LIGHTER. THE LIST IS FROM THE WAR
DIARY OF BIG MAMMIE BB59.
362 Projectiles, 16"/45 caliber H.C.;MK.13-1
362 charges, 16"/45 caliber:
Where it says 6 SPD 3633 (2300 fs) that is the lot number that particular powder came from and the FS that this lot will produce in a standard
gun with a standard 2700 pound projectile.
The next 3 lots of powder tell you that these 3 lots will produce 1900 fs when fired in a standard gun but they did not say which projectile the
powder charge is for.
Because the powder charge is for 1900 fs or reduced velocity the powder charge is probably for firing back slopes and the projectile to be used is
BB59 received 4 different lots of powder for the 16"/45 guns and 4 different lots of powder for the 5"/38 guns.
A ship always receives several different lots of powder in case there is something wrong with 1 lot, the ship can still fire.
The list does not tell what the weight of a full charge is for each lot of powder but it would have been printed on each powder can as well as all of
the above data.
THE DATA YOU SEE PRINTED ON THE POWDER BAG ABOVE TELLS YOU WHICH GUN THE POWDER CHARGE IS FOR.
THE LOT OR INDEX NUMBER THAT THIS POWDER CAME FROM.
HOW MANY BAGS ARE REQUIRED FOR A FULL CHARGE.
HOW MUCH THE FULL CHARGE WEIGHS.
WHAT THE IV WILL BE IN A STANDARD GUN WITH A STANDARD PROJECTILE.
EVERY LOT OF POWDER WILL HAVE A DIFFERENT WEIGHT OF POWDER FOR A FULL CHARGE.
IN OTHER WORDS IN A LOT OF POWDER A FULL CHARGE WILL WEIGH 665 POUNDS FOR EVERY FULL POWDER CHARGE IN THAT
LOT. BUT THIS LOT OF POWDER WILL PRODUCE THE IV WRITTEN ON THE POWDER BAG.
IN THE NEXT LOT OF POWDER A FULL CHARGE MAY WEIGH 670 POUNDS FOR EVERY FULL POWDER CHARGE IN THAT LOT.
THIS LOT AS WELL WILL PRODUCE THE IV WRITTEN ON THE BAG.
NO MATTER WHAT THE WEIGHT OF THE POWDER CHARGE OR WHICH LOT THE POWDER CHARGE COMES FROM EACH LOT
WILL ALWAYS PRODUCE THE IV WRITTEN ON THE POWDER BAG.
THIS MEANS THAT WHEN YOU CHANGE LOTS OF POWDER A STANDARD GUN WITH A STANDARD PROJECTILE WILL PRODUCE
THE SAME IV.
IN OTHER WORDS ALL POWDER MADE FOR A GUN NO MATTER WHICH LOT OF POWDER IT COMES FROM WILL PRODUCE THE
If you fire 2 standard guns with standard projectiles at the same time at the same time but each gun with a different lot of powder the IV will be the
same for each gun.
If you mix powder bags from different lots the IV will still be the same as when the entire charge is from the same lot.
You will never see anywhere in the USN Fire Control or Ordnance books anything that tells you that the IV will change when switching from one
lot of powder to another or from mixing different lots of powder in the same gun.
3B3. Powder bags
The material used for powder bags is silk, because only this fabric will completely burn away when combustion of the charge takes place, leaving
no smoldering residue to cause the premature explosion of the next charge loaded. Each bag is roughly cylindrical in shape. One end consists of an
ignition pad containing black powder quilted into the fabric so as to keep the black powder evenly spread throughout the pad. Light-weight cloth,
dyed red, is used for the ignition pad. A heavier weight of fabric is used for the rest of the bag. Bags are fitted with handling straps and lacings,
which can be used to take up any slack in the bag.
Powder may be placed in the bags in either of two ways. It may be dumped in with no regard for the positioning of the individual grains; this
produces an unstacked charge. Or the grains may be arranged in layers with the axis of each grain parallel to the axis of the bag; this is a stacked
charge. The latter results in a smoother, more compact bag and provides for faster, more complete, and more symmetrical ignition.
The firing of the separate primer used with bag guns can be relied on to set off the black powder in the ignition pad, but may not be sufficiently
potent to initiate combustion of the smokeless powder grains directly. It is essential, therefore, that each bag of a charge be loaded into the gun with
the ignition pad aft, facing the breech plug and within a few inches of the next bag or of the breech plug and primer. This factor also dictates that
the total length of the powder bags comprising a charge should be nearly equal to the length of the chamber of the gun. When, therefore, a reduced
charge is made up, the number and length of the powder bags are unchanged, but the diameter of each bag is reduced.
The powder bags used in a 16”/50 caliber gun are shown in figure 3B2. The markings on such a bag should be noted. Those on the body of the bag
indicate the designation of the gun, the index or identification number and the weight of the smokeless powder, the fraction of a full charge
represented by the bag and whether that charge is service or reduced, the initial velocity for which the charge is designed, and the initials of the
inspector. Markings on the ignition pad indicate the number of grams of black powder contained therein.
3B4. Powder tanks
Storage of smokeless powder must be both airtight and watertight if standard performance is to be maintained. The diphenylamine stabilizer
contained in smokeless powder prolongs the life of the powder but does not prevent deterioration under adverse conditions. Since powder bags are
neither airtight nor watertight, they are stored in tanks. These powder tanks are, therefore, important pieces of ordnance equipment which must be
properly maintained. Leaky tanks admit moisture and air and allow ether and alcohol volatiles to escape.
Several types of tanks are used, but all fulfill the same basic powder-storage requirements. Top covers are variously constructed but all are
designed to permit quick opening, because the number of loaded tanks allowed to be open at any one time is strictly limited by safety precautions.
All powder tanks have handling aids, the large tanks having lugs to fit slings and the smaller ones having handles.
Tanks for powder bags contain wooden spacers to prevent building of a static charge which might ignite the powder by a spark.
(Bag movement within the tank during handling causes the static charge. The spacer separates the igniter pads from the end of the tank to prevent
sparking which would ignite the black powder in the pads.)
The powder boxes are stenciled with the powder designation, the place of manufacture and the serial number of the lot. For example: IHHA Lot 40
means powder manufactured at Indian Head (IH) for 14“/50 (HA) cal. gun and that it is lot 40 of this particular caliber. Various letters such as D
for DuPont, I for International, etc., designate the different manufacturers. The last one or two letters indicate the caliber and are published in a
table in the powder specifications, for example, H stands for a 14”/45, H.A. for a 14"/50; C stands for 6”/40, C. B. for 6”/50, C.C. for 6”/53.
(m) Proof and disposition.-A firing sample for proof at Dahlgren is selected from the lot of powder and the balance is stored in a magazine until
ordered shipped by the Bureau of Ordnance. On acceptance, the Bureau gives the lot of powder a service index number which is assigned in regular
numerical sequence in the order of acceptance. These indexes are also designated by certain letters, for example SPDW 2132. The SP indicates
smokeless powder, the D stands for diphenylamine (showing it is a stabilized powder), the W stands for reworked, the number is the index
number. Other letters used are R for rosaniline (used in 1908-09 as a colored indicator of the stability of the powder but since abandoned), B for a
blend of two or more indexes, X for water dried (instead of the usual air drying), and F for flashless powder.
217. Manufacture of reworked smokeless powder.-Unstable powder from the service, odds and ends of powder from magazines, powder
accidentally wet, in fact, any unserviceable powder is sent to Indian Head for reworking. On receipt, it is dumped into concrete vats and kept under