20mm color code and odd .50 BMG

I’ve stumbled across what appears to be someone’s old ammunition collection at work and was looking for some info. I may eventually ask for help identifying the rest of the collection but at the moment I only have questions about two rounds that drew my attention. One appears to be a 20x102mm shell but I’ve never seen this color combination before and I’m a little hesitant to handle it as it is still live. The other appears to be a .50 BMG but the bullet is of an odd shape. It is next to a normal .50 BMG. Anyone have any wisdom to share?

Can you post pictures? What is the color combo?

OMG I forgot the pictures!!! I’m very sorry, here they are.

Can you show pictures of the headstamps? The 20mm looks like a dummy that someone has painted.

What is the stencilled markings on the 20mm (all of them)?

The paint job looks very self made.


Based upon the “bullet” design, this .50 BMG may well be a souvenir cigarette lighter, that is the bullet may just be a metal cap covering a lighter. Mel Carpenter wrote an article about these souvenirs in the IAA Journal #498 (July-Aug., 2014) page 43.


I took a few more pictures of both. I believe you are correct regarding someone painting a dummy 20mm. When taking these photos just now I noticed the word DUMMY can faintly be seen stamped halfway down the shell in some of these photos. I’ve never seen an unpainted dummy (usually blue?) so I suppose the aluminum tip is accurate, I know the aluminum tip is used for training rounds. I had assumed it was a live round because something is rattling away inside the case, but if I recall don’t some 20mm rounds have two thin strips of metal attached to the base of the projectile? Perhaps they worked their way loose.

In regards to the “unknown .50 BMG”, I knocked the rust off of some old callped-out calipers and found out the projectile is 14mm in diameter and shoehorned into a .50 cal case for some reason. It feels awfully light as well, so I’m at a loss as to what it could be. Since it’s some sort of fabricobbled machination I won’t feel bad if I disassemble it for a closer look.

With many years in explosives/weapons/UXO safety roles, I get very worried when anyone–and it happens way too often–refers to a “blue” paint code as “Dummy!” Not too bad in 20mm: Only the propellant and in a few cases a tracer element contain “energetics” or something that can harm you. In AT Mine Fuzes, the “blue” training–or correctly “Practice”–device explodes with enough energy to seriously injure someone NOT protected by the tank’s armor. Many blue “practice” items have significant charges to replicate the function of a war shot round, and must be treated with appropriate respect–including NOT calling them “dummy”, “inert” or any other term that could lead to minimizing that appropriate level of respect.

On another note, several earlier versions of the 20 X 102, often referred to as the “M50-series” had unpainted dummy rounds of various metal compositions, plastic compositions with metal bases/heads, etc.

Thanks for the opportunity to restate this safety message,

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Thanks for the reminder that training rounds are not dummy rounds Taber! It seems I fell down that slippery slope.

I was going off of the fact it has “DUMMY” on the projectile.
Good information to know, though!

Yeah I can’t believe I missed that Strelok! I suppose I was a bit overly cautious and didn’t want to get my face too close, I kept thinking of the 20mm horror stories I’ve heard.

It’s not as if they made it easy to read in the first place!

To complete the picture: part of the official markings on US 20mm was also a blue tip to indicate an incendiary effect.

And as Taber said, “blue” does not mean “inert” but “practice”. Two extremely different things!

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EOD what stenciled markings were you referencing in your earlier post? I’ve seen images of small stampings around the projectile near where it meets the case, but I’ve also seen printed info on cases themselves. Also EOD would the blue tip translate over to the 50 BMG comparison round I posted earlier, or does each caliber have its own color coding?

And Brian was spot on regarding the “50 BMG”! After some prying and judicious cursing I was able to remove the flimsy cap that hid the crusty lighter underneath!


Now I just need to determine if the 20mm is a one piece inert round or if it is an inert projectile in a case. The presence of what appears to be a primer in the case leads me towards the latter.

Axel, I meant any marking svisible, no matter where applied as that is always crucial for a proper ID.

The part where the projectile meets the case is the driving band (larger diameter). There is usually gives the exact projectile model designation and lot number.

And yes, for army and air force the blue on the 20mm normally is the same as on the .50 / 12.7mm and smaller.
With larger calibers the Navy used own color codes but not on calibers smaller 20mm.

The 20mm might be an inert loading. For some purposes, for example testing packaging machinery or ammunition feed systems, inert rounds are needed that exactly match the weight of a loaded round. Thus you can find dummy rounds loaded with salt, sand, or some other inert substance to simulate the powder charge. It can be difficult to tell these apart from a live round since they sound live when shaken.