USS Pampanito .50 Cal. Browning Machine Gun Mount

NOTE: These are actual working notes so there will be changes as we gather more information and correct mistakes below. There is no shame in skipping to the acknowledgments and photos near the end.

BACKGROUND:

USS Pampanito is a WW II submarine museum and memorial on Fisherman's Wharf in San Francisco. The boat is owned and operated by a non-profit and receives no government operating funds. Our preservation goal is to make the submarine as complete and accurate to our summer 1945 restoration date as possible.

When Pampanito commissioned in 1943, she had x2 .30 cal. machine guns (plus a fixed 4" 50 cal., two single 20mm Oerlikons, and more small arms). By the end of the war the number and caliber of guns were increased. On 2 Aug 1945 Pampanito had four .50 cal. machine guns with three of them stowed in pressure proof lockers on deck (plus a 5" 25 caliber wet mount gun, two Bofors 40mm, a twin 20mm Oerlikon mount, and more small arms). She had (and still has) ten lifeline stanchions with sockets for mounting .50 cal. guns. Pampanito was donated to our non-profit by the Navy in 1978 with no guns. Over the years the museum has acquired replacements for the large caliber deck mounted weapons.

This project's goal is to acquire a display .50 cal. machine gun (demilled, a "non-gun") on a historically accurate mount that we can show on Memorial Day and other special events. We also want a training cut-a-way display (demilled) that we can disassemble, reassemble, and interpet on the bench. It would be great, but lower priority to have the cut-a-way on a mount and yoke. These notes document our efforts to identify and get donated the historically correct gun and mount.

Pampanito's ship's characteristics card from Aug 1945, and the Speedletter reporting configuration from Sep 1945 say only "x4 .50 cal.". They do not specify the type of .50 cal. guns or what kind of mounts. We do not have any photos showing the .50 cal. guns on Pampanito. Change orders to the submarine gun configurations on submarines undergoing refit at Mare Island in summer 1945, including the upgrade from .30 cal. to .50 cal. AN-M2 Aircraft on E-11 mount are in summer 1945 gun and ammunition change documents. (6 MB PDF) The use of an aircraft style gun and aircraft mount on the submarine was a surprise, but is now well documented and confirmed with photos and videos from other boats. It makes sense under close examination.

We have found four combat videos from 1945 on other submarines. See the screen shots in the photo section, or watch the videos:

* https://www.youtube.com/watch?v=AYVf8TgCRy4 Near the start of the video on USS Cod
* https://www.youtube.com/watch?v=1znJcymhhGo at 1:32 on unknown boat 1
* https://www.youtube.com/watch?v=6hBYYRqtPL0 at 0:21 on USS Catfish
* https://www.youtube.com/watch?v=xi1ce9f8TOw at 0:20 unknown boat 2

For whatever it is worth, the 1959 movie "Up Periscope" at 47:24+ clearly shows two complete AN-M2 Aircraft guns with flash arrestors on E-11 mounts with E-11 back guard assembly, and Navy style yokes.

We also have a couple of still photos from other boats. Based on the information we have, we need:

* Browning Machine Gun, Aircraft, Cal. .50, AN-M2 Aircraft Flexible or AN-M2 Aircraft Basic (Index of Aeronautical Equipment 5 Armament pg 305). Either an AN-M2 Aircraft Flexible gun backplate with spade grip handles and trigger on stripped down E-11 mount (preferred), or an AN-M2 Aircraft Basic gun in a mount E-11 with complete back guard assembly and trigger lever assembly. Both mount/gun setups can be seen in the videos. The gun mechanism is very close to the M2 HB (heavy barrel) gun often used on surface ships (AN-M2 vs M2 HB). This is also close, but not the same as the late war AN-M3 Aircraft (high speed) gun (AN-M2 vs AN-M3).
DONE - Auxiliary charging handle B8583 (aka auxiliary bolt handle) is shown in the videos, not the retracting slide group assembly that is listed in submarine change order. Note with the auxiliary charging handle installed, the gun is recoiling back and forth in the mount, and the charging handle is in constant motion in the gun. No retracting slide group (normal side handle), or operating slide group (handle in rear), or electric solenoid charger, or hydraulic charger.
- No flash arrestor. The submarine change order calls for a Flash Eliminator Mark 1 Mod 0 (OP 865 pg 42), but none of the photos from other boats in 1945 show one installed. We also have a 1949 list of authorized, but not completed changes to Pampanito that includes adding the missing flash eliminator.
- No sights.
- No feed chute, no link chute adapter. The belted linked ammunition is hand fed in the photos.
- No heater.
- No electric trigger.
It seems the submarine crews removed everything they could to keep the guns light, small, and reliable.

In June 2023 we started working with TNW Firearms to acquire a display, non-gun, that cannot fit internals for display, and a second cutaway non-gun we can interpret on the bench. The ship's volunteers are working on the E-11 mount, tools, accessories and documents. We are not planning to simulate firing.

* Cal. 50 Mount Mk. 32 Mod. 0 consisting of an E-11 gun mount adapter and a yoke (from the 1945 orders):

DONE- Army E-11 aircraft gun mount adapter. For our purposes the same as Navy MK 6 Mod 3, Army E-13, Army E-5, Army GM-32, Army GM-32A, Army GM-43 (see catalog pages.) The back guard assembly, rear safety trigger, rear support with handles were stripped in most of the submarine photos and AN-M2 Aircraft Flexible gun (spade grip back plate with handles) used instead of a complete mount with back guard and AN-M2 Aircraft Basic gun. The numbers in parenthesis (x) below are from the E-11 mount parts list in AN 2011-10-25.

The first hardware that was donated for this project was 2/3rds of an original mount:
  Adapter - Gun Mount E-13.
  Ass'y Dwg. Number 7-44-6631
  Order No. W 30-053-AC-670
  Serial No. T.D. 6732
  Spec. No. AN P195
  Technical Development Co. Inc. New York City, N.Y.
Then replicas of the missing gun mounting bolts were donated.:
   (12) QA396 Spacer Front Trunnion x2 (replica donated)
   (13) 03-042-071-2 Bolt Front trunnion x1 (replica donated)
   (14) AN320-9 Nut x2, 9/16"-18, castle nut (commercial donated)
   (15) AN380-C4-4 Cotter Pin x2, 1/8" x 1" (stock)
   (16) AN960-916 Washer x2, 9/16" x 1/16" thick washer (commercial donated)
   (17) GM749-947 Slide-Rear trunnion x2 (replica donated)
   (18) 03-042-022-1 Bolt-Rear trunnion x1 (replica donated)
   (19) AN320-7 Nut x1, 7/16"-20 castle nut (commercial donated)
   (20) AN380-C3-3 Cotter Pin x1, 3/32" x 3/4" (stock)
Finally we purchased a partial E-11 mount from Australia that had the missing yoke brackets:    (3) GM749-781L Mount-Yoke Left x1 (Australia mount)
   (8) GM749-781R Mount-Yoke Right x1 (Australia mount
   (5) AN4-15A Bolt x4, 1/4"-28, 1-21/32", 1/2" of thread, hex head, cad. plated (bought commercial)
   (6) AC365-428 x4, 1/4"-28 fiber lock washer. (used originals from E-13)
   (9) GM749-927-1 Trunnion Rear Support. Our first donation has some material cut away on one side. We have seen this on other mounts so we are not going to repair swap these.

To be used with AN-M2 Aircraft Flexible gun in the stripped, minimal E-11 configuration shown in the photos we removed (reversible change) the struts and rear support from our E-13:
  7-44-6633 Rear Support Assembly and mounting hardware.
  7-44-6634 Strut Assembly (Left and Right Struts, Strut plate) and mounting hardware
Our mount was already missing the cable clips, backguard, trigger, and gun sight bracket.

To be used with AN-M2 Aircraft Basic gun (not our plan), re-install rear support assembly & struts and then we would need to acquire (we would gladly take these if offered for donation):
  03-042-454 Backguard assembly
  27 QA442 Screw-Handgrip release. For left handle in rear support, or more likely a replacement handle assembly.
  69 03-042-294 Trigger bell crank
  70 03-043-014 Spacers for bell crank
  71 03-043-015 Spring for bell crank

DONE- Yoke. Cal. 50 Carriage Mk. 23 Mod 0., Gun Mount Adapter with pintle. Or an unspecified Army Ordnance yoke. These are procured separately from the mount. They need to fit both the mount, and the sockets on the boat (we cleaned the paint out of one and it was 1-1/8".) The photos look like Navy 509684-A. Or a Bell part number GM749200, aka GM749-200 or QA361 (Bell Adapters AN 11-10-8 page 17, figure 22). The Bell documentation calls for a 1-1/8" pintle. 1-3/32" straight pintles were also common on many yokes and some of the aircraft installations used other diameters. There were several different types and constructions of yokes used with E-11 mounts on aircraft and ships.

Columbia River Maritime Museum donated a pair of yokes 509684-A-1-3. This was really special because any original yoke is hard to find. The paperwork has "Carrier Mk 23 0" which we think matches the 1945 order "Carriage Mk 23 Mod 0" so we are confident this the correct yoke. We now also know Carriage Mk 23 Mod 0 is also BUORD No. 509684 and part of BUORD Sketch 168702. FSC 1005 FIIN 3342539. This yoke has a 1-3/32" (~1.09") diameter straight pintle with the details for locking on the bottom.

- No link collection bag, or ammunition box holder, or feed chute. The links scatter on deck and the ammunition belts are hand fed in the videos and photos.

* At least one belt of links and dummy (inert) cartridges with a box for storage and transportation in the museum. A cartridge can M2 holds 105 linked cartridges, full it weighs 35 lbs.

Mark W. noted the belt in use in the video https://www.youtube.com/watch?v=xi1ce9f8TOw at 28 seconds was loaded in the following order: Ball M2 (no color on tip); Armor Piercing M2 (black color tip); Armor Piercing Incendiary M8 (silver color tip); and either Armor Piercing Incendiary - Tracer M1 (red and white tip) or Tracer M1 (red tip).

We have 58 steel dummy cartridges (drilled, brown tip) and extra links. So it would be great to find at least 47 more dummy cartridges. We bought an M2 box (storage can) online that needs coating repair.

We want a second belt of expended cartridges (no projectile) in an M2 box for use with the cut-away that will not pass a dummy cartridge with projectile.

* Tools:
See .50 cal. gun tool set (Index of Aeronautical Equipment 5 Armament pg 322-323, or Navy OP 865 pg 109-110).
DONE - Linker-delinker hand tool, Cal. .50 type M12, D7161200, 41-L-1604. Or Navy M-2, 1-M-71. This links/delinks or aligns cartridges one at a time. Also useful to combine partially used belts to create standard length belts. See TM 9-225 1947 page 45.
DONE - .50 cal. combination wrench M2 "butterfly" 41-W-3249-850 is shown in the Air Crewman's Gunnery Manual.
DONE- .30 cal. combination wrench M2 with single pin. B8696-4, 41-T-3086, or B131314 1-T-1653. The Air Crewman's Gunnery Manual show the pin on this used instead of a cartridge or punch during disassembly so it is part of the .50 cal. tool kit.
DONE - .50 cal. combination wrench M2, 41-W-867-808, D7160900. This is the type shown in the 1947 TM 9-225 manual.
- Plate type linker-delinker .50 cal type M7, 716005. This links-delinks 10 cartridges at a time and would be needed if they carried separate cartridges and links vs. pre-linked ammunition.
- Firing pin spring removal tool 41-T-3098, 1-T-1717, B243646
- Three gauge assembly A351217, 41-G-201-175, 1-G-117-50 this includes:
  A351211 headspace gauge
  A341214, A351213 timing gauges
or Headspace and timing gauge A196228
- Breech bore gauge C20623, C2623 1-G-34, 41-G-29-50
- Firing pin hole gauge A77200, 1-G-49-95, 41-G-182-200
- Cartridge case extractor 41-E-557-50, 1-E-113, C64392
- Barrel reflector 41-R-2331-25
- Cleaning rod M7 1-R-4241 D35441, Case M15 1-c-2364-20 C64274
- Release tool, C3856
- Bolt latch spring assembling tool, 41-T-3016-450
- Oil buffer removing tool 41-T-3269-75, 7319903
- Buffer spring lock tool 10-inch (aircraft only) 41-T-3315-100
- Trunnion adapter tool (aircraft only) 41-T-3378-80
- Oil buffer rod length gauge 41-G-241

* The only internal magazine storage drawing we have is from before the switch to .50 cal. so it shows the .30 cal. ammunition. (ammunition-ordnance-magazine_ss295-s7803-69623alt3_5400-11-0041.jpg) We do not have a Pampanito specific ordnance allocation list from summer 1945. The summer 1945 gun and ammunition change documents. (6 MB PDF) says there should be .50 cal. ammunition storage on bridge deck level. Combined, the internal magazines and pressure proof locker(s) should hold 4,000 rounds of .50 caliber ammunition. By our target restoration date of Aug 1945 we think it would have been shipped metal linked belted and stored in M2 boxes (105 cartridges per box) because it makes good operational sense, but we do not have documentation. It is possible it was in the can 50 cal M10 used by the Army Air Forces. M2 boxes are shown used in a ready ammunition deck locker on USS Becuna pressure proof locker drawing. We have a photo from USS Bullhead showing belted ammo being stowed in the magazine, but not what container in the magazine. We have a broader discussion of the deck stowage of ammunition in the 20mm notes on pressure proof lockers.

* Three of the four guns were stored in special pressure proof lockers on deck. Port and starboard aft at deck level set in the conning tower there are two smaller diameter lockers (they have a small diameter extension for the barrel length, gun overall with barrel is 66" long). Forward, bridge level, there is a locker that is set vertically in the deck. It was built to hold three 20mm magazines when a 20mm single was here (it is in the drawings.) Then it was modified to hold a .50 cal. machine gun (it has the long extension for the barrel). We do not know where the fourth gun was stored, probably in the handling room with the barrel removed.

* There are ten heavier lifeline stanchions with approximately 1-1/8" x 3" deep brass, 5-5/8" clear aboard. Six on main deck, four on the conning tower. Some are blocked with non-historic museum era extensions welding in place to hold a non-historic extra lifeline. The stanchions are long and welded into the relatively light superstructure which may explain the need for the aircraft style recoil absorbing gun mount. We have drawings for the original .30 cal. gun sockets that were modified when .50 cal. replaced the .30 cal. flagstaffs-searchlight-antenna-outrigger-machine-gun-sockets-direction-finder_basic490829_5400-05-0134.jpg. Look for sockets F or G. In both cases, 1-1/2" straight hole, with set screw. These were changed when they switched to .50 cal. to 1-1/8" diameter.
Note that we have a post war list of recommended changes before reactivation of Pampanito that includes replacing all the stanchion sockets with locking type. This modification was never implemented on Pampanito.

* We might also want to find or create a stand alone stanchion, or a make a socket that fits on a welding jackstand to display the gun on shore. It would be great to find enough parts to put together a second stripped down E-11 for the cut-away to display on the same stand.

* We should create a lanyard for the display gun when in the socket.

We would love to hear from anyone that has more photos, videos, drawings, or documents of submarines with .50 cal. machine guns in summer of 1945.

REFERENCE INFO:

- Browning AN-M2 .50 cal. Aircraft Flexible
Weight with back plate and horizontal buffer 65.4 lbs (this weight includes a retracting slide group we will not use.)
Length (over-all) 56.4 in.
Weight of recoiling parts 19.2 lbs.
Weight of barrel assembly 10.2 lbs.
Length of barrel 36 in.
Length of rifling 63.8 cal; 31.91 in.
Rate of fire 700 to 850 rounds per minute

Gun Mount Army Type E-11, Navy Mark 6 Mod 3
Dimensions approximately 28-1/8" x 6-7/8" x 6-3/8"
Weight approximately 11 lb, 10 oz (this includes back guard group)
A.E. Ref. 52-1300
A.A.F. Drawing Number S42D5223
BUORD Drawing 278292
Navy Aviation Ordnance Stock Number 1-A-68-13
Does not include the yoke.

- We have copies in electronic form:

* "Aircrewman's Gunnery Manual", OPNAV 33-40, NAVAER 00-80S-40, 1944. Air_Crewmans_Gunnery_Manual_1944.pdf 55.8 MB
* "Index of Army Aeronautical Equipment, Volume 5 Armament", 1944. Index-of-Aeronautical-Equipment-5-Armament-1944.pdf 49.6 MB
* "Aviation Ordnance Equipment Catalog", OP 865, 1944. op865-aviation-ordnance-equip-catalog-1944.pdf 62.3 MB
* "The Ordnance Catalog, Standard Nomenclature List No. A-38, Gun, Machine .50, Browning M2, Aircraft-Basic", Parts and equipment list. gun-50cal-snl-a-38.pdf (10.4 MB)
* "Group A, List of all Service Parts of Gun, Machine, Cal. .50, AN-M3, Aircraft, Basic, ORD SNL A-67", July 1955 gun-50cal-snl-a-67.pdf (26.5 MB)
* "Handbook of Instructions with Parts Catalog for Single Adapters for Caliber .50 Machine Guns", AN 11-10-25, 1945, covers E-11 and E-13. browning-50cal-mount-E-11-aircraft-AN-11-10-25.pdf 3.9 MB
* "Gun Mount Adapters, Navy Type", OP 1070, 1945. Browning aircraft gun mounts. op1070-gun-mount-adapters-navy-type-1945.pdf 7 MB
* "Handbook of Operation and Service Instructions, with Parts Catalog for the Gun Mount Adapters, Bell Aircraft Corp, Technical Order" AN 11-10-8, 1942.
See Figure 22 - Illustrated Parts List - Model 34
* TM 9-225 "Browning Machine Gun, Caliber .50 Aircraft Basic", 1947 On Google Books
* TM 9-225 "Technical Manual, Browning Machine Gun Caliber .50, M2, Aircraft Fixed and Flexible", 1942
* TM 9-230 "Machine Gun Mounts for Boats", 1943 On Google Books
* TM 9-1225 "Ordnance Maintenance, Browning Machine Gun Cal. .50, All Types", 1942 On Google Books
* TM 9-1225 "Ordnance Maintenance, Browning Machine Gun Cal. .50, All Types", 1943
* TM 9-1990, OP 215, "Small Arms Ammunition", 1948, tm-1990-small-arms-ammunition.pdf 16.7 MB
* WD CAT ORD 6 SNL A-35, DOA SC Group A, "Tools, Maintenance, for Repair of Group A Material"ord-6-snl-a-35-tools-small-arms.pdf 5.6 MB
* "Gunners Information File, Flexible Gunnery, Air Forces Manual 20" 1944 for B17 aircraft.
* "Weapon Mounts for Secondary Armament", G.O. Noville, 1957. This is a really extensive (1,200 pages) catalog of mostly vehicle mounts, but includes many Navy and air mounts.
* "Training Manual, Caliber .50 M2, Browning Machine Gun Aircraft Basic", General Motors.
* "Training Manual, Caliber .50 M2, Browning Machine Gun", General Motors. This one has descriptions of the differences between AN-M2 Aircraft, M2 Heavy Barrel, and M2 Water Cooled.
* "How The Gun Works, Caliber .50 M2, Browning Machine Gun", General Motors.
* "Instruction Charts (Reduced Size: Black and White) for Gun, Machine, Cal. .50, Browning M2", 1935.
* "Record of Army Ordnance Research and Development, Volume 2 Small Arms and Small Arms Ammunitions, Book 2 Small Arms Ammunition", Chapter 18-Packaging of Small-Arms Ammunition, pgs 287-320. Record-of-Army-Ordnance-Small-Arms-Ammo-Cans.pdf. History of M2 and M10 ammunition cans.
* A mixed collection of M2 HB, AN-M2 Aircraft, AN-M3, M2 gage drawings of varying legibility.
* A set of .30 cal. M1919A4 Browning gun drawings, 1949
* Several post war M2 HB manuals.

- Want to find copies:

* SubBase Pearl Drawing No. XAA-84-.50 Caliber Gun Yoke.
* Drawing BUORD 509684, yoke
* Sketch Drawing 168702
* SubBase Pearl Drawing No. XAA-86-.50 Caliber Gun Mount and Socket.
* Portsmouth Plan 69160-296 Alt 1, Buships SS296-S7803-720168 arrangement showing location of pressure-proof ready service lockers.
* BuShips Plan SS296-S7903-720411 .50 cal gun mount adapter sockets
* Parts drawings of at least one of the Bell gun mounts: Navy Mark 6 Mod 3, Navy Mark 8, Army E-5, Army E-11, Army E-13, Army GM-32, Army GM-32A, or Army GM-43
* Complete set of legible parts drawings .50 cal. AN-M2 Aircraft .50 cal.
* Cross reference between the WW II part numbers in SNL A-38 and the post war (mid-1950s+) for M2-HB, AN-M2, AN-M3. We think these might be in, "Cross-Reference of Former Ordnance Stock Numbers, SM 9-3-4", 1957, Dept. of the Army Supply Manual, 24 books. If scanned and OCR'd SM 9-3-1 or SM 9-3-2 would also work.
* "Description of Manufacture Browning Machine Gun Caliber .50, M2, Aircraft", Volumes 1-3
* "Aviation Ordnance Equipment", GPO, microfilm series reels 8-13. Really any of this series. This contains the bell adapters and AN-M2 Aircraft gun mechanism.
* FM 9-2021, TO39A-5AF-25, "Ordnance Maintenance of AN-M2 Browning Machine Gun, multiple versions." Formerly TM 9-1225 updated 1953.
* "ORD 7, SNL A-59, Gun, Machine, Cal .50, M2 Heavy"
* "Basic aircraft machine gun, Cal. .50, AN-M3" TM 9-219
* "Gun Mount Adapters, Navy Type", OP 1070, 1945. We have a black and white photo copy, and cell camera photos in color copies. We would like a proper flat scan. Available at NARA College Park, Ordnance Pamphlet collection.
* Drawings NARA College Park, RG 156: Small Arms Division, Browning .50 caliber Machine Gun, 29x37. These are training aids. We have photos, but would like proper flat scans.
* OP 1015 "Preparation, Adjustment, and Lubrication of cal. .30 and cal. .50 Browning Aircraft Machine Guns for Firing" (available at NARA College Park)
* OP 1284 "Instructions for the Overhaul, Inspection, and Test of Gun, Browning Aircraft, cal. 50 AN-M2" (available at NARA College Park)
* OP 548, "Firing tables for 0.50 caliber Browning machine gun I.V. 2,400 f.s. (War Dept. Pub. FT 0.50-F-3) M1921, M1921A1, and M2 (watercooled)" (available at NARA College Park)
* "Handbook of Machine Gun Support Equipment and Accessories 1895-1945", 2018, Segal. At least the M2 pages.

- Online references:

* Training Film 1-260, Aircraft Machine Guns and Cannons, War Department, 1941 https://www.youtube.com/watch?v=vQjdFyQ-HkM
* VBBSMYT animation of .30 cal Browning machine gun mechanism, https://www.youtube.com/watch?v=1Bf6kv1jZng
* "United States Naval Administration of World War II, Bureau of Ordnance, Guns and Mounts, No. 75", Caliber .50 AA Machine Gun, Chapter III, https://www.ibiblio.org/hyperwar/USN/Admin-Hist/075-Ordnance/075-Ord3R.html
* "The Machine Gun History, Evolution, and Development of Manual, Automatic, and Airborne Repeating Weapons', Chinn, 1951. https://www.ibiblio.org/hyperwar/USN/ref/MG/index.html
* B17 Lucky Thirteen aircraft restoration, http://hangarthirteen.org/parts-drive/armament/

REFERENCE PHOTOS:

submarine characterics card
Ship's Characteristics Card, Aug 1945. Showing x4 .50 cal.

document from 1945
This 7 Sep 1945 message documents the new gun configuration. It also lists the pressure proof lockers for ready ammunition and .50 cal gun storage, but does not specify which lockers hold what. We do not have the letter that this is responding to.

stanchion on Pampanito
Typical stanchion with socket on Pampanito main deck with conning tower behind it. Others with more room behind them are just straight without the offset on top.

socket on the stanchion
Socket is 1-1/8" diameter hole.

Photo of crew celebrating on deck
USS Balao

one crew feeding belt, one firing on main deck
USS Batfish.

crop of gun
Crop and brightening of shadows from the USS Batfish photo above. Flexible gun, no sight, no flash arrestor, hand fed.

bare chested crew member feeding ammo with gun in foreground
USS Catfish crop from film. Flexible gun, aux. charging handle, no sights, hand fed, stripped E-11 mount.

gun with yoke backwards
USS Cod crop from film. Notice the yoke is mounted to maximize elevation vs. clearance behind, this is how it is usually shown on aircraft. Flexible gun, aux. charging handle, no sights, no flash arrestor, hand fed, stripped E-11 mount.


USS Cod crop from film. Another gun position, same configuration. The yoke mounted in opposite direction from the photo above. This provides more room for the gunner between the stanchion socket and the conning tower behind him.


USS Cod crop from film. Another gun, same configuration.

gunners on deck
USS Cod 1951 photo. Post war. Flexible gun, no sights, hand fed, stripped E-11 mount.

looking down on deck mount near hatch.
Unknown boat 1. Flexible gun, aux. charging handle, hand fed, stripped E-11 mount.

with safety back
Unknown boat 2. Basic gun, complete E-11 with back guard assembly, aux. charging handle, no sights, and none of the E-13 additions.

photo of gun in use on a submarine
Unknown boat 2. Same as above.

photo of gun in use on submarine
Unknown boat 2.

belt of ammunition with different colors on the tips.
Note the different colors on the tips of the shells from unknown boat 2.

two sailors loading belt of ammo in magazine
USS Bullhead loading ammunition into the magazine below crew's mess. We think the ammunition was stored in boxes. Maybe they were returning this belt to a box that is unseen?

photo of a waist gunner
An E-11 mount in a B-17 aircraft. Heater, feed chute, and simple sights that are not used on submarines.

WISH LIST PHOTOS:

basic gun
This is the AN-M2 Aircraft Basic gun that is used with an E-11 back guard assembly. We want to use a spade grip back plate with handles to make it an AN-M2 Aircraft Flexible gun (no back guard assembly on mount).

gun on left with two barrels on bench
M2-HB, heavy barrel gun on top with its barrel, and an aircraft barrel without the its jacket below it for comparison. The aircraft version is shorter, lighter, with its jacket bearing surface near the muzzle instead of close to the body of the gun.

gauges on carpet
Typical headspace and timing gauges.

tool on carpet
Typical firing pin spring disassembling tool.

extractor
Typical broken cartridge case extractor.

tool on carpet
Combination scraper and broken cartridge extractor.

drawing of gauge
Typical breech bore gauge.

5 tools
A- Barrel Reflector C64255. B- Headspace and Timing Gauge A196228. C- Barrel Holding Wrench A152640. D- Packing Adjusting Wrench A152369. E- Firing Pin Hole Gauge A77200.

m7 linker on a bench
Plate type linker .50 cal type M7, D7107072. There are several variations of this type of linker. We are not sure if they had one of these aboard, but it seems likely.

CATALOG PAGES:

illustrations of E-11 above E-13
E-13 is an E-11 with extra parts 1-5, and wider rear support 6 in the illustration above.

catalog page with illustration
Index of Army Aeronautical Equipment, Army E-5, Navy Mark 6 Mod 3, pg12

catalog page with illustration
Index of Army Aeronautical Equipment, Army E-5, Navy Mark 6 Mod 3, pg13

catalog page with illustration
Index of Army Aeronautical Equipment, Army E-11, Navy Mark 6 Mod 3, pg16

catalog page with illustration
Index of Army Aeronautical Equipment, Army E-11, Navy Mark 6 Mod 3, pg17

catalog page with illustration
Weapon Mounts for Secondary Armament, Noville, E-11, pg 755

catalog page with illustration
Weapon Mounts for Secondary Armament, Noville, Mk 6 Mod 3, pg 260.

catalog page with illustration
Weapon Mounts for Secondary Armament, Noville, Mk 6 Mod 3, and Mk 6 Mod 4 pg 261.

catalog page with illustration
Weapon Mounts for Secondary Armament, Noville, Mk 8. pg 262. This type was bolted to the a turret without a yoke.

three mounts on a table
Three types of aircraft mounts: Top is an E-13. Middle is an E-11 with an added sight bracket on top. Bottom is an Army E-8, or E-12 which is spring loaded on the barrel instead of hydraulic on the mount frame. (Andrew Cox photo)

catalog page with yoke
Yoke 41D6865, Index of Aeronautical Equipment 5 Armament. pg 129. Quite different than the ones in the submarine photos.

cat page with arrestor
Flash Arrestor Mk 1 from OP 865, pg 42.

flash arrestor on gun
Flash arrestor on barrel in another museum. The submarine change order calls for these, but they are not installed in any of the photos/videos we have.

ACKNOWLEDGMENTS - THANK YOU!

We appreciate the advice, help, donations, discounted products, and services from individuals and companies that make our restoration projects possible. We can not succeed restoring Pampanito without the incredible generosity of these people and companies:

AeroAntique, https://AeroAntique.com
Richard Beleson
Gerard Blume, B-17F Lucky Thirteen, https://hangarthirteen.org
Master Chief (Ret) Charlie Butcher
Columbia River Maritime Museum, https://www.crmm.org
Barry Cox
Master Chief (Ret) Jim Gray
Sean Hert
Battleship Massachusetts, https://www.battleshipcove.org
Richard Pekelney
raging_deacon_arts on eBay
Sunset Books, Larry Shaw
Mike Stockton
Vintage Aircraft Inc., Taigh Raimey, http://twinbeech.com
Mark Wertheimer, USAF AFMC NMUSA/MU, https://www.nationalmuseum.af.mil
Volunteers and staff of USS Pampanito

OUR RESTORATION:

e-13 from above
With the help of David Mitten, and Battleship Massachusetts, the first hardware we received is an incomplete E-13 mount. The hydraulic buffers compress and restore with spring force nicely, there are proper lock wires on the oil fill and drain, rams are still plated, so probably good to go except for oil level. The left handle retaining screw is broken off in the handle, the right was frozen but loosened up with penetrating oil. Rear support has a crack in one of the tube flanges that could be repaired. Both strut mounting screws are frozen. Some of the rear trunnion support aft face was cut short (no idea why.)

e-13 from side
As received E-13. The left and right castings for the yoke mount, front trunnion mounting bolt hardware, and rear trunnion mounting hardware are missing. Yoke support brackets are missing. With an AN-M2 Aircraft Flexible gun we will not need the missing back guard trigger and sight support assemblies.

rear trunnion support with cut area
There is material cut out of the rear trunnion support. We have seen a similar cut on another mount. We do not know why these were cut or how common this modification was so we are leaving it as received.

bolts, spacers, slides and nuts on the bench
Replica front and rear trunnion bolts, spacers, slides, washers, nuts donated by Mike Stockton.

mounting bolts installed in mount on the bench
Replica front and rear bolts test fit, smooth.

mount, rails and backgrip separated on the bench
Mount stripped to minimal E-11 configuration. Rear support and strut assemblies removed. Still missing the yoke support brackets, and a yoke.

yoke brackts on rusty tubes
Yoke brackets on partial mount from Australia. The bronze trunnion rear support on this mount is also good, the tubes and hydraulics shock parts are wasted beyond repair. The rear support might be salvageable.

front of mount with all parts execpt gun installed.
Our E-13 configured as the minimum mount shown in the war time videos. Still needs the Flexible gun and a yoke.

top view of complete mount
Our mount ready for a gun and yoke.

mount on bench with yoke
Stripped down mount on yoke 509684-A-1-3 with 1-3/32" pintle.

mount on the bench
Another view. We mounted the yoke to provide more room for the gunner, i.e. the gun farther from the socket in the stanchion.

mount test fit showing little room between stanchion and conning tower.
There is not much room between the stanchion and the conning tower on the main deck so the offset socket and backwards yoke provide more room for the gunner.

mount on the bench
One consideration in choice of yoke is how it folds to fit with the gun in the pressure proof deck lockers.

aux charging handle on wood bench
Donated auxiliary charging handle that was used instead of retracting slide group assembly.

handle mounted in gun
Auxiliary charging handle installed in a gun, no retracting slide group.

58 dummy cartridges and 60 loose links
Found in collection, 58 dummy (inert) cartridges and links. We have more links and would like to find 50 more dummy cartridges.

linker-delinker tool on bench
M12 linker-delinker tool

cartridge being pulled out
M12 linker-delinker with the dog cam lowered, extractor cam in delinking position. Squeeze the handle to withdraw the cartridge from the link.

cartridge being pulled out
M12 linker-delinker with the dog cam raised, extractor cam in linking and aligning position. Open the handle to link (push) the cartridge into the link.

linked cartridges in can
Normally a double link is loaded in the gun first. So the single link end of the belt goes in the bottom of the box. This box is post war.

m2 box side
M2 box that might be WW II.

m2 box stencil outline under paint visible
M2 box. An earlier stencil is visible under the paint:
105 CAL .50
LINKED API-ITRM17
REPACK'D LOT LC-195782

closed latch
M2 box. Latch works, top is easily removed. Stamped, "AMM. BOX CAL. 50 M2"

logo stamped on end
M2 box. Shell & Flame (a.k.a. Flaming Bomb) Army Ordnance Branch logo. Made by Modern.

50 cal combination wrench
.50 cal. combination tool. This "butterfly" style was used for all major variants M2 HB, M2 water cooled and AN M2 aircraft. This version is shown in the 1942 9-225 AN M2 aircraft manual and 1943 SNL A-38.

an m2 50 cal wrench
Combination wrench shown in .50 cal. AN M2 Aircraft 9-225 manual 1947. 41-W-867-808, D7160900. No spanners for water cooled barrel.

30 cal wrench on the bench
B8696-4 .30 cal. combination wrench as shown used in the Air Crewman's Gunnery Manual.

 

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