A bit of fun - identify this shell

[sledgemeister]

I found this in my old mans workshop last year while cleaning it out.
He has no idea how it got there, nor does he remember anyone that would have had access to such an item.
It is approx 1 3/4" accross and 2 1/8th" high.
I have pictured it next to a lighter to give you a idea of scale.
Do I know what it is, yes I do   (there is markings on the bottom but that would give it away)
I will give you a hint their is a date scratched into the bottom - 11-6-1951

Goodluck!

PS if no one has worked it out in a few days I will post another pic showing the bottom of the case a lot clearer!

[mkm]

I will give you a hint their is a date scratched into the bottom - 11-6-1951

I don't have a clue about the shell, but do have a quick question for clarificiation.

Is the date month/day/year USA style or day/month/year everybody else style?

[sledgemeister]

I don't have a clue about the shell, but do have a quick question for clarificiation.

Is the date month/day/year USA style or day/month/year everybody else style?

Unsure, thats the way its etched on the bottom. (year probably being the most important aspect)

[tombogan03884]

40MM

[sledgemeister]

40MM

Sorry Tom - no 

[Sponsor]

[Solus]

Well, 1951 points to the Korean War period....

1.75 in converts to 44.44999 mm...so  45 mm maybe

2.125 in converts to 53.9749 mm ...  so 54 mm maybe

Google-fu is not hot for this one...

My first impression when I saw the case was that is was some type of signal gun or flare gun cartridge.  It just does not look up to handling a high pressure charge.

There appears to be a not fully expanded crimp around the mouth of the case which might indicate it contained a projectile less than the full inside diameter of the case...or maybe a non-solid projectile.

There also appears to be a very slight rim at the base of the case.

Case walls look pretty thin also.

[tombogan03884]

Flare guns were generally around 37MM.
What diameter were the Coast Guard line throwing guns ?

[Grizzle_Bear]

Is it an aircraft engine starter cartridge?

Rob

[Solus]

Is it an aircraft engine starter cartridge?

Rob

Ahhh..sounds like a great guess to me!

A great movie too.

[MikeBjerum]

Grizzle made me say you betcha, so I did a search on them based on what I knew from the past and antique engines at our local threshing bee.  Everything I find says the engine starting cartridges are 12 ga.  This doesn't mean there wasn't a variation knowing how the military works, but that is what I know so far.