37x136R heavy 1 pdr high explosive shell, USA

[pzgr40]

Cutaway model of a 37x136R high explosive shell with base fuze. It was used it two guns; the “US navy Mk IX 1 heavy 1 pdr gun” designed in 1897, and later in the 37mm Mclean automatic gun, a land based gun with a firing rate of 50 to 100 rpm.
The 37mm McLean gun was not taken into use by the US army, however 218 guns were sold to Russia in 1916/1917, and later to other countries, but all in small numbers.

At first glance one would think this is an armour piercing shell, but it is a high explosive projectile with a base fuze. The projectile body is made of cast steel. The full brass made fuze is placed in the threaded hole in the base of the projectile. The fuze has a firing pin that consists of a brass cilinder (inertia weight) with a sharp needle on top. A tensioned pressure spring is placed around the firing pin, between the top of the cilinder and the firing cap. The cilinder of the firing pin is fixated by a radial placed bras pin with a diameter of 1,5mm. Upon firing, inertia moves the cilinder backward, shearing off the brass pin on both sides of the cilinder, moving the brass cilinder backward. This moves the firing pin in the backward position, releasing the tension on the pressure spring. Upon impact, inertia moves the firing pin forward into the firing cap, riding the spring. The firing cap ignites the black powder booster charge above it, which ignites the main charge of black powder in the projectile body.

This cartridge was produced by the BSC (Betlehem steel company).

Data:
Length of complete cartridge : 210mm
Vo ; 640 mtrs/sec
Max. range : 3200 mts
Projectile weight : 476 grams
Length projectile (with fuze) : 100,5mm

Regards, DJH

 

[Gspragge]

The projectiles that went with the McClean Gun were the Driggs type with a separate base and the Driggs Patent fuze (the Navy never used it). This Navy pattern has the one piece cast body.
These were also exported commercially too unmarked and so on. The loading could also be flaked TNT mixed with the Black powder later on. There are numerous Navy fuzes, some with tracers some only tracers etc. This type was replaced (one would think old stock would be used up) with essentially the same projectile as the Army used in the 1916 gun (MK1) around 1915. Also used in the 1Pr Landing gun which was also ship mounted.

 

[pzgr40]

Thanks for the added info Gspragge.
Regards, DJH

 

[blu97]

Nice cutaway dj, ps it is going good with me again hope to see you soon erik

 

[BEAR64]

Hi pzgr40,

Excellent explanation of the base fuze workings and the shell cutaway photo compliments this superbly!

Has enriched my understanding of how the base fuze work.

Cheers,
BEAR.

 

[earni74]

Many thanks guys fr your responses, appreciated

 

[pzgr40]

Yesterday we had a colletors meeting and I bought this 37mm M3 gun HE shell of the old type (pict 01 and 02) ...or so I thought, however
some thing are not clear to me.
When looking at this movie https://www.youtube.com/watch?v=JzONIDe8DgA , between 00;20 and 00;38 one can clearly see a sharp nosed projectile with a wide driving band, looking like the heavy one pounder on a 37x223 shellcase.
The shellcase I have bought has a smaller primer in the base (pict 02), and is of the old type. However, the projectile (pict 01) has a base flange and the driggs type base fuze, but according to internet descriptions (pict 03) should have the fuze BD M38A1 (Pict 06), in fact a slimmed down M58 base fuze (or the M58 was sized up).
I therefore suspect I bought a Mclean gun projectile on a old type M3 shellcase. Can anybody tell me if this combination was used? when looking at the 37mm projectile in the drawing with the fuze BD M38A1and the one pounder shellcase (pict 05) the nose of the projectile in more rounded and the driving band is amaller.

Who can help me on this one.

 

[Gspragge]

I would think it's mixed , so you need to find a 1916 or 17 PE&M 37x136 case for it. The projectile band should have USA stamped on it ?

 

[pzgr40]

I think I'll be lucky to find a shellcase 37x136 at all over here, let alone a 1916 or 1917 shellcase, and especially one that is also PE&M marked.

 

[pzgr40]

Found the correct shellcase with the PE&M stamping :rock:

 

[pzgr40]

Here the high explosive cartridge with the Driggs base fuze for the 36x136R McClean gun. With the driggs base fuze the firing pin is being held in aft position by a safety pincer with two collar halves on the loose end that fit the groove in the back of the firing pin. The forward end of the pincer with the ring is pressed in the base of the brass cap housing the firing pin. After firing, the centrifugal force forces open the pincer, releasing the firing pin to move forward upon impact. The firing pin wil hit the firing cap, which explodes. The flame of the firing cap travels through two channels into main charge cosisting of a black powder /TNT charge, exploding the projectile.
In contrast to the heavy one pounder projectile that has a one piece body, the projectile of the McClean gun has a screwed in base plate housing the Driggs base fuze.