40mm Bofors questions, U.S. Navy

A friend of mine was a loader on a 40mm Bofors gun mount on a U.S. Navy ship in the mid to late 1950’s. His recollection was that the ammunition came already loaded on the four round clips, four clips to a can. Years ago while visiting the U.S.S. Texas, I noticed that there were compartments located behind some of the quad 40mm mounts labeled as “40 mm clipping rooms”. To me, this implies that the 40mm ammunition came packed loose and had to be loaded into the clips before use. There were racks all along the bulkheads for holding loaded clips, so this room was also a ready magazine of sorts. Did 40mm ammunition come packed two different ways or did it change sometime during or after WWII? As substantial as these clips are, they do seem to be intended to be reloaded manytimes…



By the time I was in the Navy, the 40mm had been phased out on all of the big ships so I did not have much exposure to them. What I do remember is that the ammunition in the ready rooms, ready lockers, and magazines was clipped. Here’s a photo that has been all over the internet (and this Forum) that shows how I remember it.

But, since the 40mm fired thousands of rounds during an engagement it makes sense that they could eventually run out of ammunition. Perhaps the ships did receive cartridges that were not clipped, stored deep in the bowels, and the “clipping room” was used to assemble the loose rounds? I don’t know how the loose rounds would have been packed. Maybe someone else can tell us.


I was in the “Gator” Navy (Amphibious) in the late 50’s and just about all of the WWII Commissioned ships (AKA, APA, LSD, LST etc.) still in service still had their dual and quad 40mm mounts as armament. All the 40mm ammo aboard these ships came in 16-round cans (4 4-round clips as was mentioned before). After a firing exercise, the empty cases would be gathered up, placed back on clips which were returned to the cans. The cans were then returned to magazine storage until they could be returned to an ammo depot.

I’ve never heard of 40mm coming in single round form (unclipped) but I never served on a battleship either.

What was done about the cases that inevitably ended up in the water if they all had to be collected and returned? Did it matter that some were missing?

One of my lecturers in college was in the Royal Navy in the Falklands era. He said they were supposed to return empty 4.5" Cases to the magazine. He always saw this as pretty pointless as so many ended up in the sea.


There was no requirement that all fired cases be accounted for. We simply had to report the total number of rounds that had been fired. All empties that were recovered were stowed until we returned to a port that had facilities to take them, for whatever fate awaited them.

The RN at the Faulklands were like US sailors in every way. Many of the empties were “lost” overboard. Maybe helped along with a boot. The brass cases were like cash in the bank. Many a swabbie found one in his locker or under his bunk and, of course, the Gunners Mate found a carton of cigarettes in his locker or bunk.

Even projectiles were seldom returned to the ready room or magazine. Much easier to toss them overboard and add them to the number of rounds fired. Those suckers were heavy!


Here are some of the canning options:

Rick, the brown box is a British one, I guess we can exclude this on US ships.

And some clip variations. There were apparently as many different clip designs as there were manufaturers. I’ve collected 7 and have seen a half dozen others. My latest was made of plastic. Odd.

And that clip in the left of the picture is wrapped in a cosmoline saturated cloth. Still has the original sticker on it. Can only imagine sitting next to a five gallon bucket of diesel with a scrub brush, prepping hundreds of them for use.


Roger that. Was just showing that to note the single loading vs all on clips. EVERYBODY used the 40MM Bofors, so packaging/shipping options were quite varied.

Rick, sorry for nitpicking then. Yes I noticed that there are quite some interesting variations in US clips for the 40x311R. I wonder if somebody ever has attempted to assemble a guide on them.

Haven’t seen much of anything on the clips. And I’ve been searching. Nothing even in TMs or FMs. Somebody, somewhere, had to have documented specs on these things. Numerous manufacturers produced these in various forms. Can’t even imagine how many types are out there. Odd how there are tomes written about .303, Cal. 30, etc clips but not a peep about the Bofors stuff. Hmmmm.

Any US Navy 40mm empty cases being lost overboard during firing operations would probably have been intentional. After firing, the empty cases were deposited in front of the gun mount inside the gun tub via the case discharge chutes. It would be rather difficult for the cases to get out of the gun tub without some help. As you can see from the photos quite a lot empty shells could build up during heated attacks.

Everything you ever wanted to know about these:

I’ve talked at length with a member of the CV-10 40mm gun crews from 1944-1945 and specifically asked him about the loose cases in the tub. He said his assistant loaders, the guys in the tubs recovering the ready-service ammo, tried to empty out the boxes in front of the gun 1st because it soon became nearly impossible to walk on all the cases. They kept a big shovel too and when someone had the opportunity, they started shoveling them over the side. He said he didn’t know what others did but while he was on the 40’s, that was his recall. He did not recall much interest in saving fired cases, just getting fresh live ones up to the gun as quickly as they could.

Photos from a recent discussion in a Facebook ordnance collectors group - a project is underway to rebuild 1200 rds of 40mm bofos ammo to refill the racks and bofors tracks of the USS Kidd. The projectiles appear to be reproduction aluminum. To be painted in the typical red, green, and black colors to replicate original shell types. The Kidd is a museum ship, and is the best remaining example of the WWII era Fletcher destroyer class.