5"/25 Round?


#1

Does anyone have a picture of this round? I’m under the impression this was a one piece fixed round but I know little more about it and searches on the web havn’t been very fruitful. I’ve seen a vidio of the gun being used but views of the ammo were poor.

The 5"-25 Naval Gun was used on US submarines in WWII and used fixed ammunition because of the physical restraints of submarines. They replaced the early 3" gun and were used very effectively in the later period of WWII in the Pacific. I just don’t know much about the ammunition itself.


#2

Shotmeister,

If you haven’t already, check out this great website: navweaps.com/Weapons/WNUS_5-25_mk10.htm

They don’t have a pic of just the 5"/25 round, but you can see them being lugged around in pics here: navweaps.com/Weapons/WNUS_5-25_mk10_pics.htm

I would say it’s fixed ammunition by the looks of things in how they put the whole deal in the fuze setters. They mention the Mk 17 as being semi-fixed loaded, though, specifically for submarine use.

Dave


#3

Dave’s right that it was fixed for surface ships, semi-fixed for subs.

Curiously, I can’t find any reference to the case dimensions in any of my sources (except one that’s clearly wrong!).


#4

I did not realize, until today, that the 5"-25 was even used on surface ships. Just thought the 5"-38 was always the standard there.

Tony, you are far wiser in these matters than I but I have talked to veterans and read accounts that say that fixed rounds were used on subs. Of course, I am not even sure what a semi-fixed would be! There is a compartment on the base of the conning tower, a watertight tube, where ready service rounds were kept and reportedly they were in metal, water-proof containers which were opened and the round taken out, then to the gun. There was a elevator like tube from the magazine (inside the pressure hull) to the gun deck where additional ammo could be passed up. Seems like anything other than a fixed round would be very difficult to handle inside a submarine! I’m pretty certain that there was no fuze setting device on these guns because they were not intended to be used against aircraft on a submarine, strictly surface action only. They were used against small craft, such as wooden boats, which didn’t justify a torpedo.

The USS Cod’s website has some cool photos of the gun and associated stuff on that museum boat in Cleveland Ohio. It’s prestine and could probably fire right now!

Thanks to you both. The more I learn the wiser I become!

Chief Shot


#5

5 INCH 25 FIXED


#6

Indeed on that there are artillery with not fixed rouns
Surcouf des FNFL (poured by mistake by an US cargo boat)
p-j

en.wikipedia.org/wiki/French_sub … 28N_N_3%29









#7

I can confirm the information given about the ammunition on www.navweaps.com. Here are some pages from "U.S.Navy Projectiles, 1945 "
Hope I can find me a case some day ?







#8

[quote=“TonyWilliams”]Dave’s right that it was fixed for surface ships, semi-fixed for subs.

Curiously, I can’t find any reference to the case dimensions in any of my sources (except one that’s clearly wrong!).[/quote]

TENDS TO GET CONFUSING WHEN THE NAVY SHOWS 2 DIFFERENT CASE LENGTHS BUT SAYS THEY MEASURE THE SAME.


#9

[quote=“Shotmeister”]I did not realize, until today, that the 5"-25 was even used on surface ships. Just thought the 5"-38 was always the standard there.

Tony, you are far wiser in these matters than I but I have talked to veterans and read accounts that say that fixed rounds were used on subs. Of course, I am not even sure what a semi-fixed would be! There is a compartment on the base of the conning tower, a watertight tube, where ready service rounds were kept and reportedly they were in metal, water-proof containers which were opened and the round taken out, then to the gun. There was a elevator like tube from the magazine (inside the pressure hull) to the gun deck where additional ammo could be passed up. Seems like anything other than a fixed round would be very difficult to handle inside a submarine! I’m pretty certain that there was no fuze setting device on these guns because they were not intended to be used against aircraft on a submarine, strictly surface action only. They were used against small craft, such as wooden boats, which didn’t justify a torpedo.

The USS Cod’s website has some cool photos of the gun and associated stuff on that museum boat in Cleveland Ohio. It’s prestine and could probably fire right now!

Thanks to you both. The more I learn the wiser I become!

Chief Shot[/quote]

Traditionally there were 2 types of artillery ammo; 1) fixed and 2)seperate loading. 1) fixed-obvious- one piece ready to go into the gun. 2) seperate loading-projectile , charge and primer all loaded a piece at a time time-thus seperate loading. A third type was developed later in which the cartridge case containing the powder charge and with primer seated was loaded seperately. This is called SEMIFIXED pr sometime SEMIFIXED SEPERATE LOADING.

WHY? historically there were 2 basic types of gun sealing devices 1) German Krupp sliding wedge and 2) French DeBang interrupted thread .

The Krupp design required a case to seal the tube. The DeBang used a bag charge and a seperate primer. In general these 2 types are still in use today.

Fixed ammunition is only good up to a certain size. That size being what a man or 2 can carry and load.

The 5 inch 25 is pretty near the top of what a manual loader can do. If you look at the photos of the dry 5inch 25 reference above you will note that the shell are ready stored bottom up near the gun. These shells are fixed ammunition. If they were not the projectile would fall out of the case when it was lifted.

Semifixed ammo is easier to store in 2 shorter pieces.

There has been fixed ammo fielded over the years which required 2 men to load the shell. This was never a good idea. Slow to load and twice the problems.

The web page or the submarine “COD” in Cleveland ,refered to above, says

“Cod’s Ammunition Scuttle and ready-use ammo locker. The 5”/25 gun fires fixed ammunition—that is, the shell and cartridge case are fixed together at the arsenal where they were manufactured, and don’t have to be handled separately. Several rounds can be stored in the pressure-proof locker for immediate use. The pipe-like scuttle leads down into the pressure hull, and ammunition is passed up through it during a gun action".


#10

So it seems that the 5"/25 ammunition on subs was fixed? I would take the first hand accounts of submariners over a web site’s info any day! In looking into the references I have, I don’t see any other references to the semi-fixed ammo for the 5"/25, or am I missing something?

Sorry if I led you to bad info, Shotmeister!

Dave


#11

[quote=“DaveE”]So it seems that the 5"/25 ammunition on subs was fixed? I would take the first hand accounts of submariners over a web site’s info any day! In looking into the references I have, I don’t see any other references to the semi-fixed ammo for the 5"/25, or am I missing something?

Sorry if I led you to bad info, Shotmeister!

Dave[/quote]

The matter seems unsettled to me. 5 inch 25 ammo is decribed as fixed and semifixed in official literature. Where the SF was used has not been demonstrated yet. It may be that some subs carried both to fill what space was available.

There is a description of moving the ammo from storage to the deck on one site and it went through several hands. Could be that the ready ammo on deck was fixed and that components were stored well below and passed up as needed.

This is the kind of info which could have been had from all of those hundreds of folks who were looking at this site when the torpedo thread was cooking. many of these fellows were VETS with real sub experience.

AMMUNITION collecting has no size , shape or rules ( except when the government gets in it) so the more experience which is brought to the table the easier it is to answer questions.

Example of the nonsense of governments. The US NAVY requested that the WW2 era ( 1945) Navy manual on projectiles and fuzes be removed from the internet for “reclassification consideration”.

After 65 years in the public eye !!!


#12

This is the very 1st Inert item I ever purchased way back when I was 12. I was told that it is a drill round for the US Submarine 5" Deck Gun???

Jason

A Rubbing of the HS


#13

Some very interesting and useful information being posted here!

My source is “Naval Weapons of World War 2” by Campbell - an excellent reference which has quite a lot about ammunition scattered through it, and recently back in print after being unavailable for many years. Having read it more carefully, I can add some more info.

The surface-ship 5 inch L/25 guns were Marks 10, 11 and 13 (with various sub-marks, e.g. Mark 11/5). These all fired fixed ammo. The submarine version of the gun was the Mark 17, of which there were two sub-marks: Mark 17/0 and Mark 17/1. Campbell states that the Mark 17/1 was adapted to fire semi-fixed ammo, and implied that the Mark 17/0 fired fixed rounds.

So there’s your answer - both fixed and semi-fixed ammo was used in submarines, depending on the Mark of gun.


#14

“The submarine version of the gun was the Mark 17, of which there were two sub-marks: Mark 17/0 and Mark 17/1. Campbell states that the Mark 17/1 was adapted to fire semi-fixed ammo, and implied that the Mark 17/0 fired fixed rounds”.

“Adapted to fire semifixed”- I wonder what that means.

Where are all those submariners when you need them ?


#15

[quote=“APFSDS”]This is the very 1st Inert item I ever purchased way back when I was 12. I was told that it is a drill round for the US Submarine 5" Deck Gun???

Jason

A Rubbing of the HS

[/quote]

It is a beauty - could be a sub dummy shell. Quite a load for a 12 year old.


#16

Yeah, that’s what my parents said when the UPS man delivered it :-)

I purchased it from a classified ad I found in one of my fathers issues of Shotgun News. It came as 2 pieces, projectile and case. It was fascinating on how the projectile attached to the case with some type of spring loaded locking mechanism. I have never been able to separate the projectile from the case since they were attached.

Jason


#17

Now that begs the question; is this a seperate loading dummy or a fixed dummy and are there 2 types for the 2 types of guns.


#18

I am really not sure? This dummy /drill round was definitely designed to have the projectile attached to the case. There is a big metal button on the side that needs to be depressed in-order to unlock and release the projectile. So far, I have not had the strength to press it down.

J


#19

Jason’s round is very, very nice! Perhaps it is a drill round from a submarine.

As a member of USSVI I have access to a good many WWII vets and I have talked to several I know locally. Though none were on the gun crews they all said the guns used fixed, one-piece, rounds which were stored in the ready service locker and magazine below the mess decks. Some of these men recalled handling the rounds when they were loaded onboard but none of these men knew the designation of the rounds or the type of rounds.

Submarines during the war were fitted with 3" and 4"-50 caliber guns as well as the 5"-25’s. Most had one gun aft but some had 2, 1 forward, 1 aft. There were three boats, Argonaut, Nautilus and Narwhal, that had 2 6"-53 guns which did use 2-piece rounds. One of the veterans I spoke with was on an S-boat with the 4" and recalled it as having “a loooong barrel”. Though a Corpseman, he wasn’t impressed with that gun but his Fleet boat had 2 of the 5" guns and he desribed them as awesome and effective against the small “truck” boats they encountered in 1945 around Japan.

My expectation from this thread was to see one of the rounds used with the sub guns, certain that someone had one or at least a picture. Never expected to learn so much about the 5"-25 that I did not know! Though I am fairly certain that subs used fixed 5" rounds, perhaps some did not. (Never say never) None of my vets ever saw the 5" used against aircraft and they described explosions typical of HE rounds. Nore had anyone seen dummy rounds used or drills on the guns except during live fire, either practice or combat. Jason’s round may have come from a school or training unit.

Anyway, its been a fun topic and thanks to all for their efforts. Jason, hope you can squeeze that latch to get your round apart. Tried Wheaties?

Chief Shot


#20

[quote=“DrSchmittCSAEOD”]“The submarine version of the gun was the Mark 17, of which there were two sub-marks: Mark 17/0 and Mark 17/1. Campbell states that the Mark 17/1 was adapted to fire semi-fixed ammo, and implied that the Mark 17/0 fired fixed rounds”.

“Adapted to fire semifixed”- I wonder what that means.

[/quote]
It is information, merely not certainly. His exact words concerning the Marks 17/0 and 17/1 is that they were “adaptations of the 25-calibre AA gun for submarines, and in the Mark 17/1 firing semi-fixed ammunition.” What other interpretation would you put on the statement other than that the Mark 17/0 did not use semi-fixed ammunition?