20mm M55 A2

[27Division18]

What gun is this for? It is US and if so what period/conflict? It is marked 20mm M55 A2.

[917601]

20mm x 102 Vulcan (M39, M50, M61A, M61A1, GAU-4, Mk. 22 Mod. 2). The case should be 102mm tall. What are the stampings on the head case? 

[27Division18]

2 hours ago, 917601 said:

20mm x 102 Vulcan (M39, M50, M61A, M61A1, GAU-4, Mk. 22 Mod. 2). The case should be 102mm tall. What are the stampings on the head case? 

There are no markings on the base of the she;; casing that I can see. Is this for the Vulcan Gatling gun? What conflict would these shells have been used in?

[RayRay]

Volcan Gatling gun. A-10 warthog plain for exp. Gulf war era. 90’s-00s

[917601]

The A10 uses a GAU 8 30mm. The 20mm was used primarily in fighters. Judging by the picture, yours appears to be 60’s era as a guess. Without the case length ( in MM) it is hard to pin down exactly. The 20mm lineage has many variations, most having to do with case length ( power).

[917601]

I had some spare time to pull up the TM on your 20mm. The M55A2 is a target practice round - earlier issue I suspect as it is not the current correct color- blue. It could date to the 50’s , 60’s before the blue color was fully instated. Most of the modern day 20mm, 25mm …do not use brass cases, but steel alloy.

The other one that has the aluminum nose is a different model- does it unscrew? Most likely an incendiary round, the cap unscrews revealing a cavity that was filled with incendiary composition. Can you make out the ink markings on it? Or the engraving on the driving band? The cannons it was used in were : M39, M50, M61A, M61A1, GAU-4, Mk. 22 Mod. 2. You can pull up those cannons by the M number. Eg, GAU-4 Vulcan, used in fighter aircraft, M39 earlier 50’s to present for fighter acft...The case primer is electric. I do know a bunch of these projectiles were surplused out years ago (1970,1980’s) before the practice was discontinued and all are now scrapped.See the TM data sheets. I also am including a picture that has a .50, 20mm API, 25mm HEI, 30 mm TP ( A10), and 40mm L60 Bofors.

[917601]

For the 20mm in use on the F16.

https://www.f-16.net/f-16_armament_article5.html

[917601]

More :

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

Notice your links, modern era is link less, that would suggest my early timeline, 1960’s, identifying the link ( check for any link markings) would give you the exact time ( era) stamp. 

[RayRay]

On 11/7/2021 at 3:08 PM, 917601 said:

The A10 uses a GAU 8 30mm. The 20mm was used primarily in fighters. Judging by the picture, yours appears to be 60’s era as a guess. Without the case length ( in MM) it is hard to pin down exactly. The 20mm lineage has many variations, most having to do with case length ( power).

 Thank you for the correction. Knowledge is power 

[Bodes]

On 11/7/2021 at 3:08 PM, 917601 said:

The A10 uses a GAU 8 30mm. The 20mm was used primarily in fighters. Judging by the picture, yours appears to be 60’s era as a guess. Without the case length ( in MM) it is hard to pin down exactly. The 20mm lineage has many variations, most having to do with case length ( power).

These are the depleted uranium rounds....Bodes

[27Division18]

Thanks for all of the information fellas.