Rimless-Grooveless 12 Gauge Orbea Primera Cartridge

I been trying to identify this cartridge for the past 15 years but I’m still wandering about its purpose. I assume it’s some kind of front loading flare, industrial blank, engine starter, etc. It’s made from a Spanish made Orbea Primera shotgun shell. The rim and some of the head has been deeply machined.

Light blue topwad with number “5” (looks like made by Orbea in Argentina). Brass washed steel head. Original Spanish Orbea Primera primer.

Head diameter = 19,51 mm
Neck diameter = 21,97 mm
Total length = 62,69 mm.

Any ideas?

Fede - why do you call this “rimless-grooveless?” Although the rim seems scant compared to a normal shotgun shell, there is clearly still a rim on the round in the photo. Just wondered. I think of Rimless-grooveless like the 5 mm, 6.5 mm and 8 mm Bergmann rounds.

It looks to me (and Fede’s description) that the “rim” is at the mouth/right end of the shell, with the left/tapered end housing the primer.
I wonder just how much of that “rim” would be left after the shell goes off?

Well, it has no rim or groove on the head. The “rim” over the case mouth is just a cardboard washer glued in place. It has no purpose as an extraction rim.

Fede and Tailgunner - o.k., you are right. I did not pay attention to the headstamp photo being at the wrong end - that could have been an accident in placing it. I was looking at the rim at the mouth. Sorry about that. I should keep my nose completely out of any of these things that don’t deal with auto pistol - my New Year’s Resolution. I am wrong all the time lately. I hate that because I just am confusing the newer collectors, I am sure.

Could it be a home-made cartridge, from an NPE, for some sort of early or transitional ignition system? Something designed to circumvent early patented breech loading systems?

Does it contain shot?

Probably not as you think it might be a flare or such, it might be for some sort of tractor starter? Seating on the ‘rim’ even though it is glued on, or perhaps the rim acting as a seal or spacer?

Perhaps someone has access to military tool manuals for devices might help. It would also know the time of the hulls manufacture.

Probably for a Variation of the Marshal (British) Tractor Engine starter.

Argentina in the early part of the 1900s (up to WWII) was a big user of all sorts of British-made agricultural machinery.
The carboard “rim” could be a simple “holding rim” for an ignition chamber which was connected in a reverse manner to the normal Marshall system ( drop in cartridge, screw FP cap on, hit FP with hammer–Bang–Engine turns over.)
THis Modified system could have used an entire Front Loading chamber, which screwed onto the Ignition duct/cylinder head, and the shell had to have the rim removed to place the primer against the firing Pin. Then the entire assembly was screwed/bolted onto the Cylinder head, and fired.
When the Firing chamber was removed, the shell could be Picked out, or Fall out, and a new one fitted. The card wad “rim” with the central hole helped vent the flash into the cylinder, or it just served to place the shell in the chamber; Most likely it disintegrated on firing.

Interesting “Home grown” variety…probably a shortage of British made original shells during WW II brought out this “conversion”.

Regards, Doc AV
AV Ballistics

Merry Xmas!!!

I think we should know its weight to know if it have shot or ball.
If it is a cartridge to start enginas it must be lighter than normal cartridge.

My family have a Field Marshall Tractor.
I remember the engine starter on the low front right side.
They told me the a 16 Ga cartridge was used after they cut the fron end and discart the shot.

Hope this helps.

Merry Christmas to you.
I find your breadth of knowledge to be outstanding, and you force myself (and others that are new to the hobby) to think before responding. That’s how we all learn, isn’t it?
BTW, I’ve noticed that you’re correct a lot more often than you’re in error (and that I’m grossly wrong a lot more often than I’m even close to being correct)

Like John, I probably should not poste on a thread that I know nothing about. I have no idea what this cartridge is made for, but it appears to employ a tilt breech of some sort. The breech block would tilt for loading and then tilt back intothe “fire” position. The paper washer could provide a bit of a seal and/or could hold the cartridge in position of this breech block was opened on both ends and swung back against a firing pin block. A starter system may be a good bet because a tilt chamber/breech would allow easy loading in a cramped area like an engine compartment-perhaps on an aircraft.
Just speculation.



This cartridge is not loaded with shot. Its weight suggests it holds a small compressed charge of powder (is not as heavy as a mortar propelling charge).

I don’t think this is a front ignition cartridge. The top wad thickness would not help. The primer is still in place to fulfill its ignition purpose.

Another possibility is that this could be some sort of spotting charge for a practice bomb.

Thank you all for your comments.

The primer looks Russian, as fitted in the Baikal cartridges (Azot) Different writing though.

Well, I finally found the answer: it is a Spanish propelling charge for a signaling/line-throwing projectile for marine use. The design is covered by several patents applied by Pirotecnia Oroquieta between 1950 and 1972, a company that still exists and is currenlty part of the British Chemring Group.

The glued cardboard washer “hangs” the cartridge (5) in the tail to be striked by an entering rod with a firing pin. The base is protected by a cap (7) that must be removed before firing.

Also, the original packaging was found, which is nothing more than a sealed green plastic bag without inscriptions.

Hope this is interesting.



nice response

the system is similar to wwI “taube pigeon” and italian brixia with a proppeling cartridge in the tail
but is the first time that i see a modified 12g cartridge