XM101 cartridge and projectile (at Greater St. Louis Air & Space Museum)

[The Artist]

We have this object in the Greater St. Louis Air & Space Museum and we're not sure what it is. It is not on display. I think it showed up in a box of misc. parts that had been in storage. The item breaks down as shown in pictures two and three.

Any ideas?

 

[SOC]

Looks like a fin-stabilized round of some sort. If you showed it without the rear cowling I might've guessed mortar round, but the whole thing does look like a bullet. Can you measure the diameter?

 

[Orionblamblam]

Holy crap. The one looks like the spotting round from a Davy Crockett nuclear recoilless rifle. I imagine it's not, or perhaps a spotting round from something else, but I'll look in my records.

If it's *really* heavy, then that might be it, what with all the depleted uranium...

 

[The Artist]

I didn't measure it, I just took a few quick photos after the curator asked me if I had any ideas about it today. Estimating - based on my memory - would have it standing about six or seven inches tall when stood on the flat end. It didn't feel overly heavy for its size.

I'll go prepare the detail photos I took (too big to upload as they are) and add them to this thread.

 

[The Artist]

Pictures 4 and 5 are the front and back of the rear housing. 6 and 7 are the back and front of the middle section and picture 8 shows the tip of the nose cone. The nose cone is threaded and screws into the front of middle part. The middle part is held in place by friction when the whole thing is assembled.

 

[Orionblamblam]

Ummm. I've looked at my records, and what you have is worthless. Of no interest to anyone. It will be a burden on you, your associates and your descendants, so, me being the generous, giving sort of guy I am, even though it's a hardship on my part, I'll give you a shiny new $20 bill for them, just to help you out.

Do not bother looking at the attached images. They will be of no interest.

 

[SOC]

Ummm. I've looked at my records, and what you have is worthless. Of no interest to anyone. It will be a burden on you, your associates and your descendants, so, me being the generous, giving sort of guy I am, even though it's a hardship on my part, I'll give you a shiny new $20 bill for them, just to help you out.

Do not bother looking at the attached images. They will be of no interest.

Pay no attention to Scott, he's just mad that House won't be continuing after this season ;D

 

[The Artist]

Well Scott, it's not a burden on me - the museum will have to deal with that burden.

Thanks for those pages. They give me something to think about - the round pictured in those pages does have some differences in the shapes but the basics do match. You mentioned depleted uranium. Any chance this could be a round from an A-10 Warthog?

I'd like to send those pages to the curator (listing you as the source) but I'll wait to hear back from you first.

 

[SOC]

That's definitely not an A-10 30mm round. I've got one of those myself, both the spent casing and a post-impact business end.

 

[Orionblamblam]

Well Scott, it's not a burden on me - the museum will have to deal with that burden.

They, being a busy museum, have enough to worry about.

Any chance this could be a round from an A-10 Warthog?

Very unlikely. The shape of the case pretty much precludes use in a rapid fire gun.

As for the use of DU, this was done to make the spotter round have the same ballistics as the Davy Crockett warhead. The spotter round would have to follow pretty much the exact same trajectory as the wahead, so that when the spotter round was on target, you'd know the warhead was on target.

The spotter round and gun might have been modifications of a pre-existing design, or the Davy Crockett system might have been used for another system later. But it sure does look like your little toy. Same overall shape, same three circular features in the base of the case (which is steel in the diagram and looks like steel in your photos), same fins.

I'd like to send those pages to the curator (listing you as the source) but I'll wait to hear back from you first.

Go ahead. But also pass along my needlessly extravagant and generous offer...

Compare the size of your item with the dimensions in the diagram. If it has the same overall length, and is a 20MM diameter round, then i think you've got it.

Additionally, when you next examine it, bring a magnet. The body of the XM101 was made from a moly/DU alloy (labeled 5 on the diagram). This should make it hard like steel, but not magnetic.

 

[The Artist]

Thanks Scott.

We have a mutual friend at the museum. You could always run your generous offer past him.

Mike

 

[westlucasworks]

Looks like a fin-stabilized round of some sort. If you showed it without the rear cowling I might've guessed mortar round, but the whole thing does look like a bullet. Can you measure the diameter?

these remind me of the 50mm bushmaster chain gun EAPS round

 

[Tony Williams]

Lots of discussion and info about these rounds on cartridge collectors' forums, e.g.:

https://forum.cartridgecollectors.org/t/m101-20mm-davy-crockett-spotting-round/32940/26