20x102 Projectile driving band stampings


#1

I have an inert 20x102 round with an unmarked case as usual (ink stampings long gone). The projectile driving band is stamped:
HVM-20-73 57 20MM M55A2

Can anyone give me an explanation o the meaning of the first part of the markings before 20MM. Thanks in advance for your help. This is a TP projectile, should it be painted ligt blue? It is currently un painted and slightly rusty.


#2

Falcon,

“HVM” stands for Harvey Machine Co Inc. 19200 South Western Ave, Torrance, CA 90509, USA.

Reference: MIL HDBK-1461a

Best regards, Rob


#3

I think your projectile should be black. I don’t know when they switched from black to blue for TP projectiles, but I have a M55A2 round dated 1960 that has a black projectile with white lettering. I have one dated 1965 that is blue, so presumably the change was in the early 60s.


#4

Thanks for the info Rob.

Which of the numbers in the stampings is the date?


#5

Falcon,

I think the date in the code is the “57” and I’m inclined to agree with two-az that your vintage of TP should be black.

Dave


#6

I forgot to add that the “20” is the interfix number and the “73” is the lot number for the projectile.

Quoting from MIL-STD-1168A, the lot number identifies items that are “manufactured or assembled by one producer under uniform conditions and which [are] expected to function in a uniform manner.”

From the same publication, the interfix number identifies lots “which have been produced or assembled by the same manufacturer at the same location for the same item, made according to a specific design and manufacturing process using like materiels in accordance with certain administrative procedures.”

MIL-STD-1168A is 65 pages of rules governing ammunition lot numbering, and is an excellent cure for insomnia :)


#7

So as it has the “interfix” number, does that mean that the whole round was made and assembled by Harvey Machine Co Inc.?

Looking closer at the projectile, I can see traces of black paint. I will probably re-paint it


#8

I believe the info in the driving band only references who made the projectile. The company that loaded the round would have stenciled their info on the projectile (their code, lot numbers, etc.).

This is the info on the driving band of the round I mentioned above:

  • HA 5-16 60 20MM M55A2 *

On the same round, this is stenciled on the projectile in white ink:

20MM BALL
M55A2
LC-22-246

So Harvey Aluminum made the projectile on my round, and Lake City loaded the complete round.

There should also be manufacturer/lot info stamped on the side of the case by the case manufacturer, but this often wears off.

If you’re looking to restore the markings, while there’s probably no way to determine who loaded the round, LC would probably be a safe bet. I don’t have a ton of 20x102 rounds, but the majority of mine seem to have been loaded by Lake City. Then again, that could just be because I’m in the US!

I hope this helps!


#9

Thanks for the info. I may re-paint the projectile, but I have no idea how I would do the lettering. As it is a US made projectile, can I safely say the round is likely loaded in the US?


#10

I think it would be reasonable to assume it was loaded in the US, although I can’t say for sure whether components were imported/exported.

I have seen restored projectiles with stenciled lettering that looked pretty authentic, but I have no idea how to do it. I can’t imagine it is done freehand, but then again I may just be projecting my own lack of artistic ability on others!


#11

I would think that it is most likely printed on with a roller that is put against the projectile as it is rotated. I would think painting them by hand would be near impossible.

Although my round is very tarnished now, it appears to have been polished sometime in the past, which removed all the markings. I wil probably just stick with re painting the rusty projectile for now.