577 revolver Thick Rim?

Hi all

I was looking for information about this 577 revolver cartridge (unit on the right). The thick rim is causing me headache. I will appreciate some information on it. It is a 577 revolver cartridge? manufacturer?


Thanks in advance

Looking at the base of the cartridge, I would suspect a .50 remington pistol, could you check the bullet diameter?

I have a similar cartridge also drives me crazy.
At first I thought it was a shortened Spanish Berdan cartridge. But, the thickness of the rim is very different from the Spanish Berdan cartridge.

I consulted with a top expert and he told me that he thought it was a fake made with an American Berdan cartridge.

I could agree with him but in my cartridge there is a small raised mark, which in my opinion could be a 5, a 3 or an S and I do not know any about any 58 American Berdan with that marking. This marking is raised, not stamped, which indicates that it was made during the manufacturing process.

Looking for the origin of this cartridge I followed the track and it came from the collection of the Central Artillery Park.

Does your cartridge have any headstamp? Where does your round come from?


Nice to know that there are other similar unit there, then the possibility to be a fakes is reduced :) . Nice investigation, I liked the x-ray!!!

I found this unit in my country (Uruguay) and it came from the Rubio’s collection (very old collection and well-known collector from Uruguay, he passed away last year so we cannot ask him). It was within the 577 revolver units.
This unit does not have any mark, just a small “line” following the circumference. Taking into account the non uniformity aspect, it is most probably caused by some defect in the material or stamping process.

Just for reference and following Laurent suggestion, this is a picture with a .50 rem navy. The diameter of the rim is 19.4mm and the thickness is 2.10mm.

Thanks in advance

I have 25 different .577 revolver variations and none of them look like that one (original post). I also have a near mint Tranter M1868 .577 revolver and another Belgium .577 revolver. That thick, rounded rim would never chamber correctly in either gun; it’s way too thick. Plus, the bullet looks funky, not original. If you are in the U.S. and want to send me the round for verification (will it chamber or not) in either of my revolvers, I’ll be happy to do the test.

I do not think it’s a revolver cartridge. The revolver head space is in the rim and it is so thick that even with great tolerances it could not close. At first I was suggested that it could be for a rolling block type gun. Anyway I find it curious that these two cartridges appear at 10000 km away.
How thick is the rim on your cartridge? And the rest of his measurements?

Is there in fact no cartridge in the French thick rim family, the conversions from pinfire, that this could be? That would at least answer the very thick rim seen here. Jack