NAVORD OCL A28-45 Base Detonating Fuzes Assembled in Gun Ammunition Projectiles
(Mn2a), 17 May 1945
(Ref.: (a) NavOrd OCL A39-44 dated 19 May 44.
(b) NavOrd OCL A89-44 dated 27 Dec 44.) (Enc.: (A) Table Indicating Moistureproofing Status of (Herewith) Base Detonating Fuzes.)
1. Recent investigation has indicated that base detonating fuzes assembled in gun ammunition deteriorate progressively over a period of time due to the action of moisture and other chemicals present in explosive “D” on the mercury fulminate primer now used in base detonating fuzes. A method of reducing such deterioration by moisture-proofing base fuzes with a lacquer and varnish finish has been developed. Issues from continental Ammunition Depots have been made with projectiles assembled with moistureproofed base fuzes for some time [beginning June, 1944]. The Bureau is also developing a new primer mix which is expected to be much more stable than the present mercury fulminate, primer.
2. Base fuzes assembled in TNT-BP loaded projectiles are known to perform satisfactorily even after being assembled for many years. This is probably due to the negligible amount of free moisture and other deteriorating chemicals in the TNT-BP burster charge as compared to explosive “D.”
3. Incomplete tests to date indicate that non-moisture-proofed base fuzes perform with a small percentage of duds after being assembled in explosive “D” loaded projectiles for about one year, and after two years’ assembly an appreciable percentage of duds can be expected with non-moistureproofed base fuzes. A very high percentage of base fuze duds will be experienced in ammunition assembled over three years with non-moisturcproofed base fuzes. Performance of individual lots of non-moistureproofcd base fuzes may be better or worse than the above generalities Satisfactory performance is expected of moistureproffed base fuzes even after being assembled in explosive “D” projectiles for several years.
4. Enclosure (A) indicates the moistureproofing status of all lots of base fuzes assembled in explosive “D” loaded projectiles. It is recommended that all explosive “D” loaded common and armor-piercing projectiles assembled with non-moistureproofcd base fuzes be replaced at the earliest opportunity with projectiles assembled with moistureproofed base fuzes. Projectiles of the oldest loading date (date of fuzing or last refuzing) should be given first priority of replacement.
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5. Since A.A. common and H.C. projectiles are assembled with nose fuzes in addition to base fuzes and are largely fired for antiaircraft and bombardment purposes, it is not planned to replace in advanced areas A.A. common and H.C. ammunition assembled with non-moistureproofed base fuzes. In antiaircraft fire, base fuze action is superfluous. When A.A. common and H.C. projectiles assembled with non-moistureproofed base fuzes for over two years are to be fired for shore bombardment, it is recommended that point detonating fuzes be used to insure projectile detonation. In general, A.A. common and H.C. projectiles have been fired at such rates that the majority of such projectiles in the fleet assembled with non-moistureproofed base fuzes are less than two years old. During continental availabilities vessels should replace A.A. common and H.C. projectiles assembled with non-moistureproofed base fuzes.
6. The mark, mod, and lot number of base fuzes and the date of loading and fuzing of the projectile may be obtained from ammunition data cards or by inspection of the projectiles. Information regarding the identification of ammunition is contained in reference (a). Ammunition assembled or refuzed with base fuzes subsequent to January 1945 may be considered to be assembled with moisture-proofed base fuzes without reference to enclosure (A). If assembled or last refuzed with base fuzes prior to March 1944, ammunition may be considered to be assembled with non-moistureproofcd base fuzes without reference to enclosure (A).
7. Common and armor-piercing projectiles assembled with non-moistureproofed base fuzes turned in for replacement in accordance with paragraph 4 should be forwarded to advance area Magazines and Depots authorized to refuze base fuzes, or returned to the continental United States in accordance with reference (b)
8. Continental Naval Ammunition Depots have been directed to issue only projectiles assembled with moisture-proofed base fuzes.- BuOrd, G. F. Hussey, Jr.
STATUS OF BASE DETONATING FUZES
Base Fuze Status
All original unreworked lots are non-rnoistureproofed.
All rcworked lots, stamped with “R” after lot nninber are muisture-proofed.
All lots are non-inoistureproofed. All lots are non-moistureproofed.
20 20 20
All Macon loaded lots are moisture-proofed.
Naval Torpedo Station loaded lots 1 1 li r o u g h 67 are non-moistureproofed.
Base Fuse Mk Mod
Status Coelisig Interval
Naval Torpedo Station loaded lot 68 and higher lots arc moisture-proofed.
All lots are non-moistureproofed.
Lots 1 through 25 are non-moistureproofed.
Lots 26 and higher lots arc moisture-proofed.
All lots are non-inoistureproofed.
0. 1, 2, 3
4, 5, 6, 7, 9.
10, 14, 16
Lots 1 through 917 are non-moistureproofed.
Lots 918 through 949 are moisture-proofed.
Lots 1 through 23, 1001 through 1076. 2001 through 2109, 4001 through 4137 are non-moistureproofed.
Lots 24 through 1000, 1077 through 2000, 2110 through 4000, 4138 and higher lots are moistureproofed.
3l 0 Lots 1 through 20 are non-moisture-proofed.
31 0 Lots 21 anil higher lots are moistureproofed.
Lots 1 through 40 are non-moistureproofed.
Lots 41 and higher lots are moisture-proofed.
All lots arc non-moistureproofed.
Lots 1 through 63 are non-moisture-prootcd.
Lot 64 and higher lots are moisturc-prooted.
Lots 1 ttirough 7 are non-moistureproofed.
Lots 8 through 29 arc moisture-proofed.
All lots are moistureproofed (Army fuze used in 3″/50 AP).
Cancelled and Superseded by O.C.L. A 12-4-46