Geco 5.56 by Thun

I received some Geco 5.56 NATO 55gr FMJ stuff today. These are 50rd boxes with plastic 10rd stripper clips, and the box says “Made in Switzerland”. These have a “T” headstamp for Thun, and I am overall impressed with this whole deal whereas it was $260 with free shipping for clipped Swiss-made 5.56! The plastic stripper clips seem good quality and feel like a glass-filled polymer type of product. I took one close-up photo of the markings on one.

I suppose the question now is, has Thun gone the way of Norma and become sort of a brand-name only of RUAG’s which is not necessarily representative of the long history of quality product?


Hi Matt, I enjoyed your store yesterday, Great Job !
I see it has a military crimped primer, is it boxes primed?
I have notice a lot of GECO Brand coming into the country for a little over a year now in many calibers, 38sp, 357 mag, 380. 9mm etc… I have shot a lot of it along with Prvi and S&B brands, no complains and good prices. Sure it must be making a big dent in domestic production.
With NAFTA gone we’ll see if that changes in the future.

I would be extremely surprised if it was Berdan primed, all modern European military 5,56 I’ve seen was Boxer primed. Including some Thun ammo I have, with “T” over “11” headstamps.
There are some “hybrid” cases, which use two holes like a Berdan case, but is primed with a Boxer primer (the “Berdan” case has no anvil between the holes). However most are pure Boxer (Boxer small rifle/1 single central hole).


Ole, DAG and MEN also do (mainly?) Berdan as it is in the specs for the Bundeswehr for example.

So all depends on the customer. I assume for the commercial market Boxer is ruling these days.

Current Swedish and Norwegian service 5,56 ammo (CG/Nammo VV) is Boxer brass with Boxer primers FWIW.


I guess Berdan is still being made here simply for the reason that the specs have never been changed in decades. And to the military relaoding is no option so why changing?
But the day may come.

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Interesting about the 2 holes for boxer prime, must have no primer pocket stem.
Never seen that , I will have to remember , they can reloaded, but maybe an issue de-priming the case?
Thanks for the info.

Maybe my information about Bundeswehr ammo is dated, but according to it

  • the 5.56 mm (DM11, DM21, DM31, DM41) use a Boxer type primer (DM1465) with a case that has two flash holes (like the 9x19 DM51).
  • the 7.62 mm variations use a Berdan type primer (now using heavy metal free primer DM1440).

By the way, the 55 gr bullets of the Geco box from Thun replicate the U.S. M193. Printing “Nato” on the box is at least misleading.

Could it be that these cartridges were actually made in Germany by (former) DAG? The deep headstamp is not ‘Thun like’.

Here’s an example, CG “green” FMJ-P (two-part mild steel core with tombac jacket), with the 2 hole case and Boxer primer.

As you point out, you need specialized tools to de-prime, for example a deprimer die with off-center deprimer rods, or a hydraulic deprimer tool.


Thank you for sharing, very interesting.

The making of cases with smaller than normal flashholes, or double berdan flash holes withboxer primrr cups is a form of ammunition control, done under pressure from the UN to prevent reloading by revolutionaries and civilians etc…Started by Singapore in the 1980s…
Small flashole on 5.56, HO date, and 7.62N by Hirtenberg, it is now common in Geco 9 Para used by France’ FL and Police, and seversl other European Makers…
But the naive bureaucrats have no idea about the resourcefullness of reloaders…smaller diameter decappers for small FH, and hydraulic for any Berdan case!!!
I get tons ( yes, tons) of good quality Geco 9mm cases from French Polynesia ( FFL) and use a Dillon 1050 Regular with workshop-made decap pins,to decap, pocket swage, and FLS. Then a FH uniformer in a semi-auto mini lathe ( own built) to rectify the FH to normal. .presto, cheap reliable 9mm cases.
Same for SFH 5.56 as well.
Doc AV.

NOT A reloading topic, but a manufacturing detail!!!

When I was a kid we had many 7mm & 8mm military rounds that were practically free, and there was a supply of Berdan primers available.

When we wanted hunting rounds, and factory ammo was scarce and/or to expensive, we filled the cases with water [I do not remember who taught us that, but I suspect it was the owner of the old Davis Gun shop [in Falls Church, Va., that closed in the 70s’] and used a bullet diameter rod to push out the primers.