37MM with "Broderick Plug"

Hello, this is my first post here and I hope I’m in the right forum section. I recently picked up some 37MM Hotchkiss casings and projectiles and most I’m familiar with. One stands out as unfamiliar simply due to the base plug. I also am not sure if this is live or not so I’m not handling it much and will proceed appropriately based on the feedback I receive from you gentlemen.

It appears to be a Naval Armor Piercing round but is it HE? Is the plug a fuze or just a plug? Do I have something here I should be concerned with?

This looks to be a US made “Heavy 1 pounder” projectile. This was used with a longer case than the 37mm Hotchkiss.

With British shells of similar age, anything stamped with “P” or “PLUG” usually refers to a solid inert plug in place of a fuze. These were used with practise rounds which were filled with an inert substance to replicate the weight of explosives.

However, I cannot say that this is true for American ordnance.

One way to get an idea as to whether it was filled or not would be to compare its weight to a known empty example.
Most importantly, always assume that an item is live until proven otherwise by a competent person.

hipwr223, The round is a 1pdr as Falcon stated. It stamping indicates it was made by the American Ordnance Company in 1898. The use of a “PLUG” denotes the same thing in the UK as it does here, also as he stated. It IS unusual in my limited experience to see the plug have the makers name on it. Nice round and even nicer plug. Cheers, Bruce.

Bruce, in your opinion is this an inert projectile? It came with a slightly longer 37MM brass case marked UMC Bridgeport.

If there are traces of gray paint on the projectile, I think I can see some, then it’s a Common. It looks as though the plug has been removed at some time in the past. Someone used a pipe wrench on it, I think. It should unscrew with little effort. It probably has a left hand thread.


The remnants of the paint actually is more gold colored and this concerned me. My mind starts to create “what if” theories. Like what if it was a British contract? Gold paint on Brit rounds is HE correct?

Left hand thread! That’s why it felt tight, thanks Ray. This place is a wonderful resource.

Glad to help.

That’s a Common projectile. Contained an explosive (usually black powder) with a base fuze to light it when it struck a target. With the Plug it was most likely a target projectile filled with sand.



Would be possible for you to take a photo of the projectile base markings with the plug removed?

Nice projectile & plug!



hipwr223, you couldn’t be more spot on! Nice projectile also!

Someone who actually knows what they are talking about needs to correct me on this.

1 Pounder (1 PDR) and 1 Pounder Heavy (1 PDR H) actually refers to the gun, not the ammunition. The cartridges are usually headstamped as such, although, I believe that the ammunition is interchangeable and can be used in either gun.

Below are two cartridges so headstamped.



Would be possible for you to take a photo of the projectile base markings with the plug removed?

Nice projectile & plug!



For those who care about such things - I’ve been informed by a 37mm expert that the cartridge on the right in my photo is a Subcaliber round. Fired for sighting purposes from a subcaliber gun mounted on larger guns in turrets. It would have been blank loaded, with a tracer.

So, you can correct your catalog listing for that cartridge, if you want. ;-)