5 inch 54 Navy case

Can anyone tell me the difference between the 5" 54 Mark 7 and the 5" 54 Mark 9. I have the Mark 7 and it is a brass case. a friend has a Mark 9 (Which he got to fire himself) and his case is steel. While were at it, what is the Mark 8.


Being an ex 5"/54 Gunners Mate I should know this - but I don’t. I used the MK 6 which was the original post WW II case for the MK 16 Gun. The 5"/38 that it replaced used the MK 5 case.

So, I’d guess that the MK 7 and those that followed were the improved iterations. The improvements could have been minor, such as heavier case walls to take the beating of Rapid Fire mechanisms, or something major such as a change in materials such as brass to steel.

What are the dates on the cases?

The MK 16 guns were sold to the Japanese navy when our Midway Class carriers were disarmed and they could even be from that use.


Ron & Ray,

The 5"/54 Mk.7 Mod.0 is also brass, and is dimensionally the same as the Mk.6 Mod.0. It has a different drawing number, and weighs .06 lbs. more than the Mk.6, but the difference in weight is not explained in OP 2215, “Navy Gun-Type Ammunition”, Jan. 1959. The Mk.10 Mod.0 case is made of steel, and is much shorter, with a length of 26.75" versus 32.93" for the brass cases.


Jim–Thanks for the information. What is the specifications
on the Mark 8 and Mark 9 cases.

Ray–Are you saying the 5 inch 38 Mark 5 is just part of the same series and could be fired in a 5 inch 54 gun? I have a 5 inch 38 Mark 5 which is 26.65 inches compared to my 5 inch 54 at 32.85 inches (Both lengths are converted from the length in mm to the nearest mm)

So, Jim or Ray, can you give me the specifications on the entire 5 inch series, Mark 1 to Mark ??


I suppose that the MK 5 could be fired in a 5"/54 just like a 45-70 could be fired in a 45-90 but I can’t imagine it being done. The projectile would come up short of the throat, for one thing, and the powder charge would not be appropriate.

I haven’t a clue as to where you would find the specs for the entire 5" series of cases. Don’t forget, there is a whole series of 5"/54 guns from the MK 16 all the way up to todays modern RF systems. Cases would be designed accordingly.

It’s interesting to note that the 3"/50 RF cases MK 7 and MK 9 are brass and steel respectively, with nary a MK 8 to be found. Maybe that means something, and maybe not.

Again, what are the dates on the cases?


I’d say that the MK 7 brass case was probably an improvement over the MK 6 and was developed for the 5"/54 RF guns as designed for the Forestall Class carriers.


Ray–I have no idea what the date is on my Mark 7. It is in a storage locker about 15 miles away. It has to be in the 1960’s or before because I sent it home from Vietnam in 1968. Same for the 5"/38 Mark 5. My friends Mark 9 is 1973.

This is what he had to say about his:

“Here’s my 5” 54. I fired it from the forward mount aboard the USS Luce DDG38."

I asked him what it was like to fire the big gun. He said:

“All you heard inside the mount was the noise of the loading mechanism. Sort of a twang sound when the round fired, but no bang at all. It was well vented, but a very strong ammonia smell came from the firing. I was buddies with and hung out with the “Gun Guys” so I was afforded that courtesy. Sadly, I could not reciprocate, but they understood.” (My friend was a Gunners Mate-Missiles)

I would have thought it would have been quite loud, but after his answer, I realized that most of the “BOOM” is at the end of the barrel, not the breech.


The LUCE had a single MK 42 RF gun and the steel case would have been appropriate for it. It’s likely that the brass case could have also come from a MK42 gun although the Midway class carriers served in Viet Nam and still had a few MK 16 guns on them at that time. In the 60s those would have been the only two 5"/54 guns in service, AFAIK.

The noise level inside a 5" mount is not exactly like a library although it is quieter than most would realize. The noise of the machinery is always present. I would describe the sound of the gun itself as more of a muffled boom followed by the whoosh of the air ejection system. Tossing the powder case and the projectile onto the loading tray makes a loud clank but that is not typical of the RF guns because the case and projectile are not touched by human hands twix the magazine and the gun.

Since the gun crews were made up of ordinary seamen the hardest part of a Gunners Mate job was to keep them from skedaddling when the shooting started. Dogged hatches, made even tighter with a rawhide mallet, helped.

Boy, I miss those days. ;) ;)


Hey Ron and Ray

That guy from the Luce said he defers to Ray’s assessment of sound level inside the turret. Considering that 2 rounds fired does NOT constitute any sort of knowledge or experience, and said shots fired some 30+ years ago, there is no arguing the facts of Ray’s experienced hand. And the fact the loading mechanism was a hyrdaulic-electric-pneumatic affair, the humming din and slamming of shells and projectiles around made for something of a sensory overload. Sound powered phones have never been known for their sound SUPPRESSION qualities. That’s what the Luce guy said. And that it was a hoot. But what does he know?


OK. The cat is out of the bag. Slick Rick was the source of the quotes. He is a Friend, and a good one. I still say it must have been great fun to fire those big “Boomers” when it is not your normal job.


When Ron said that his “friend” was a GMM, I thought, Hmmmm, that sounds familiar. I hope I got the dope on the LUCE correct.

Usually, a non cannon-cocker is so overwhelmed by what is happening inside a gun mount that they hear little, if anything. As you called it, sensory overload.

But it happens to all of us. I remember the first time I watched one of the RF 5" guns being fired. It was all so fast that all I could say was, “WTF just happened?” ;) ;)

And I really do miss it. Sorta. I was always so busy working that I didn’t have time to really enjoy the experience.



Your specs on the gun sound right. I read all about that a while back. The GMGs were less enthusiastic during the exercise, considering it work, and the fact they had to do the cleaning and PMS while I was in line at the gedunk, waiting for the movie to start.
Had a supervisor at work the other day, in an attempt to motivate a couple of folks, do the old two finger twisting motion. Asked him if he thought they understood the “prompt” and he advised he did have to explain what TURN TWO meant. He was an OS a few years back. Warned him I might start having flashbacks if he wasn’t careful.


While the 5"/54 (yes Ray) Mk 42 gun mounts and ammunition were an important armament, let’s not forget an another important shipboard swatter. The Terrior missile.
Here’s a great shot of the missile magazine. Found this on a Navy webpage. In order to maintain an “ammuniton” theme, knowing this stretches it a bit, can we just consider it a single nozzle gyrojet? In a BIIIIIIIIG stripper clip?
Defined as an APFSIHE-N (Anything Piercing Fin Stabilized Incendiary High Explosive or Nuclear) Beam Riding or Homing, Mach 4 missile. The color banding was, “busy”. There is no headstamp. Electric primer. Actually a RIM-67-ER Standard misslie.

The guy sitting is at the EP-4(A-side/starboard) panel, which had controls for pushing the missile up out of the magazine, onto the rail, and shifting it forward about a foot. The guy standing is next to the Fin Rack, skating.
The place was kept cleaner than the mess decks. Everything shiny , that could shine. After PMS, there wasn’t much else to do but polish and paint.

And then there’s this pic. This is a -N version.

I made up that APF… stuff.

My 1945 Navy manual list the brass 5" Navy gun cases as follows:

Mark 3 5"/51 caliber 33.05" length
Mark 5 5"/38 caliber 26.75" length
Mark 4 Mod 0 & 2 5"/25 caliber 24.65" length
Mark 6 5"/54 caliber 32.93" length

I don’t have info on the steel cases, but they were all different mark numbers.

SHELSHUS–Thanks. That fills in some more of the gaps in the Mark numbers.