Casing identification


I have a casing with no markings and am attempting to identify the caliber. The casing measures 4" in length and is 1 1/8" in diameter it has a rim and is tapered



It would be a big help if you could post pictures showing the cartridge case profile and cartridge case head (base) with primer.

Rim diameter measurement?

Case material? Brass, copper, aluminum, steel, plastic/polymer?




You might also try reposting your question in the General Ammunition Discussion section of the forum, this will assure maximum viewing of your question.



Brass casing 4" length 1 1/8" diameter no markings


Looks like an electric primed 20x102mm Vulcan, for the Air Force.

The Navy used the came basic case but in a 110mm case. The Navy doesn’t worry too much about the extra weight, as it just makes a very slightly bigger hole in the water.

For the future when stating the diameter, you need to give the base that you show plus the bullet dia. which in this case would be the inside of the mouth. Makes it a lot easier on everyone to provide you with a quick and proper answer.

As Brian notes this would be better on the General Ammunition Discussion section. Perhaps a moderator can move it?


Yes sir, I have more that I need identified, sorry I wasted your time and



Nothing like a good mystery cartridge, so your questions are not a waste of time. If you have more questions please don’t hesitate to ask.



And please take separate images of the hs and side view of the cases to be identified.


No wasted time on my part, glad to be of help. I was just trying to explain how to present the information so to be of mutual benefit.

In this game anyone is liable to turn up something none of has seen or can’t easily identify. So any help with measurements, materials, or printing / stamping is of value.

If you have more bring em on!

I should mention often subtle differences in cases make one different than another so accurate measurements are important. In most if not all cases tolerances in ammunition manufacture are of great importance, as with dealing with things that go bang, so measurements need to be accurate & precise.

I apologize in advance if you feel I might be talking down to you, it’s only because I don’t know your level of interest or experience, but do want to be of help.

Glad to see you got moved to where more will see your posts & welcome.


I do appreciate the help and I dont feel that you are talking down to me at
all, any new information is great because I am a novice but I do have a
high level of interes


I didnt know if I had posted these pics yet, so I apologize if I have.