Pinfire Shotgun Cartridge


I was digging on an archaeology project at the site of an 1820’s plantation, west of Houston, Texas. The attached image shows one of the things that we discovered. I’ve identified it as a 16-gauge pinfire shotgun shell base, made by Eley Brothers, London, England. Eley apparently started making these shells about 1828.

If I know what it is, then why am I here?

What I would like to know is how to tell if the cartridge has been fired or not.

In a pinfire case, the protruding pin extends down inside the sidewall of the base of the shell to a primer mounted on the inside. The hammer from the firearm hits the pin, driving it into the primer, causing the flash to ignite the powder.

So, what happens when the hammer hits that pin? Does the pin get crushed? Does it just move it downward a millimeter or so to activate the primer? What outward appearances are there that might indicate a pinfire shell has been discharged, when all you have is the brass base like this?

Any guidance would be appreciated.

We have also found many other cartridges on this site, like the Henry with the dual firing pin marks. And even some .22 rimfire cases, missing the bullets, but with no firing pin strikes, leading us to believe that the bullets were pulled to get to the powder to use it for some other purpose. Interesting stuff!


Hello JohnRich,

From the outside of a pinfire case it is almost impossible to see if it is fired or not, as you say the pin wil be driven inside for a mm or two. For the rest the pin wil stay intact as before.
Second Eley Bros didn’t produce these shells as early as 1828.
Their first pinfire shotshells are produced around 1868 ( could be wrong a few years ). These headstamps show the year of production. So the head you have is probably late 1870’s or 1880’s

Regards rene

PS perhaps somebody can give a more precise manufacturing date.


As a primer, a pin fire shell normally uses a percussion cap which the pin strikes from the inside, not the outside as on a conventional cap & nipple weapon. The interior recess of the case it’s self would act as a support for the cap and the anvil or in this case pin, when struck would ignite the fulminate & fire the shell striking it from the inside.

Hope this is of help.

Also in looking at the visible height of the pin in your photo I’d guess it has been fired. Also a look at the interior would be helpful.

Polman: FYI an Eley London headstamped brown (third class) paper shell exists with a 1861 date as part of the raised headstamp.


Thanks Pete,
I was just lookinig at it.
According to C.W.Hardings book ELEY CARTRIDGES
All headstamps that carry a raised headstamp and contain the name Eley Bros or EB is from the period 1861 and 1874.
This should give a good indication of the period.

Regards rene


Thanks for the info, guys.

The inside of the base was caked with dirt, and as an excavator my tools were too crude to clean it up to see the inside clearly. That’s the job of lab technicians who will get their hands on it next. I’ll have to wait to see what they reveal of the condition of the primer on the inside.

So it sounds like from what I’ve got there isn’t much of a way to know if it’s been fired. You would need an identical unfired case to compare with side by side, to note the length of the protruding pin. And that difference isn’t going to be very much.


A very knowledgeable person might be able to tell by deformation of the cap once you get inside. Depending of course on its condition. The hammer strikes the pin hard enough to ensure reliable ignition and a percussion cap is only thin foil. So with luck the pin will have left a witness mark on the cap. Here’s hoping anyway.


An unfired loaded (brown paper) shell in my collection of the same gage & headstamp measures 8.17 mm / .322" long on the outside


If the cartridge has been fired the primer should, I think, be distorted and perhaps with splits in its sides. If unused, the cap should look pretty much like a typical percussion cap, tho probably more slender than typical. As Vince has pointed out, even if it was a dud, the firing pin should have left a visible strike on the inside of the cap. Jack


Some pinfire pins have a shoulder and a reduced diameter inside the cap. The shoulder prevents the pin being driven down into the cap without a very positive strike. This feature made them safer to handle, especially if fumbled and dropped. When the hammer hits the pin it drives it inside the cap and the cap is stretched/split as the larger diameter part of the pin enters. So, an unfired pin/cap of this type should be fairly easy to recognise.



The familiar splitting of caps on muzzle loaders is a function of the charge pressure coming back out through the nipple and so is not likely to be found in this application. On my single shot M/L pistol full charges blow the cap each time and the cap drops off the nipple as soon as the hammer is lifted. With half charge target loads the cap is stuck tight on the nipple and requires a small pair of pliers to ease it off.

How a cap would be affected by being within the charge is speculative. Would it be collapsed inwards or would it appear unaffected because the pressure is all around it equally on all sides?


Vince: I concede your point about pressure deformation of the cap in a pinfire cartridge versus a conventional percussion cap. As far as deformation of the cap in a percussion arm is concerned I think that vent diameter in the nipple is also a factor. I’ve noticed that nipples with larger vents seem to deform caps more severely with a given powder charge than other nipples with smaller vents. I once knew a percussion rifle that would re-cock itself due to an enthusiastic reaming of the nipple vent. Jack


I too have seen this, indeed I can get it to happen occasionally on the m/l pistol of which I spoke if I overload it. On rifles I believe it is quite common. Nipples wear out from the inside and the hole gets enlarged by gas errosion and use.
Many old muzzle loaders have very large vent holes in the nipple. Whether they started out that way is hard to say.