Need your help Identifying this cartridge

[Deelayed]

https://en.wikipedia.org/wiki/M61_Vulcan

Is that on the roster ?

[beerman]

Still puzzled by the conventional primer on the OPs round. Vulcans ( and all other American 20mm) have electronic primers. I’ve had many and all had the EPs.

[Subotai]

Yep, had some as a kid.

[CoopsDad]

Solothurn 20x138 maybe?

[Rwnielsen]

Good lord what ever it is I wanna see the device that is used to propell that projectile.

I imagine somebody, somewhere, has fabbed up a Contender barrel for it.

[SVT-40]

It's as said above a 20mm dummy. Specifically "M51A1" Lake City made in 1985 Lot#B226.

I have a similar round in my collection. It's in the center of the pic to the right of the inert Chinese stick grenade.



Pic below of 30mm dummy rounds in their stripper clip for manual loading into the gun on the Apache helicopter.

[ar15barrels]

It's as said above a 20mm dummy.
Specifically "M51A1" Lake City made in 1985 Lot#B226.

I think I have one of the same ones.
I paid a dollar or two at the SAR show a few years ago.
I can't imagine they have gotten to $15 or $20.
That price would likely be for a live round which the OP does not have.

[hambam105]

I have one of those too. It's iner....BOOM!