Interesting report on 37MM, XM415 (Davy Crocket Spotter)

Once more I’d like to invite everybody to post documents of interest for use by our community.



Thanks for posting a very interesting report. Does anyone know how the XM415 differs from the XM446E2 cartridge? From the CASE BODY drawing LCA-SK-423 in the referenced report it seems the XM415 has a rimless case while the XM446E2 fired case I have as a reference is rimmed. Is this the main difference or are there others of note? Also, as the 11-62 date on my example post dates the the XM415 info, is it safe to assume that the XM446E2 was the version that was deployed for use in the XM77 gun on the 155mm launcher? What other versions are out there? Does CSAEOD have a nice sectioned example of the 37mm spotter he would like to share a picture of?

I have these on VHS tape but not up to getting stills out of it yet. I’ll look for something if someone else doesn’t get to it first.


Could you possible put some photo’s here of your XM446E2 cartridge?
Here are some photo’s I saw on Ebay a while ago.


A nice clean one. Thanks.


Nice pictures of a very clean example. I will work on getting pictures of the XM446E2 case posted. Interesting that the XM415E7 is rimmed as well. The XM446E2 is very much like the pictures you posted except there is no groove where the (2) spanner holes are on the base and has no “zone” indication in the head stamp. Lot number is PA-274-3. The report from the original post indicated that the number of spanner holes was also an indication of range zone.


Can someone assist me with another novice question? What does “Spotter” mean in relation to ammo?

Jason–A “spotter” round is usually a sub-caliber round used with a larger type and has the same ballistics as the larger, more expensive round. It is fired to “spot” the impact point and is usually designd to explode with a puff of smoke or a bright flash. Presumably, if the “spotter” round is on target, then the main round should be also.

Thanks again Ron! Appreciate that allot.

I went back to EOD’s posting of a very interesting report since “Crockett Spotters” came up again. It seems the 20mm spotter body was DU per discussions in GaryM’s recent post and most info on the web is about residule contamination concerns at ranges where they were used.

The 37mm report for recomended modifications to the XM415 described as the “E3” variant suggests that the projectile body was steel and the only DU was the “Counter Weight” cylindrical slug to increase spotter material payload. The case is also rimless and shorter (260mm) and different in profile. (see below). These were recomendations that may not have evolved as the XM415E7 picture posted show a rimmed case profile very similar to the XM446E2 as far as I can see.

Question: Was this case ever actually made and was the DU “Counter Weight” adopted on later versions of the 37mm Spotter and if not, was any DU used at all.

Any input on the evolution of this round and it’s fielded variants would be appreciated.

I’m starting a full model of the complete round from the drawings in the report posted by EOD. Here’s the case as recommended by the report.

Thanks, Dave

Here’s the whole deal per the report posted by EOD.


Really nice drawing Dave.

Thanks, Falcon…

Here’s the projectile alone in a more “sexy” pose.


I seem to be getting photobucket’s “image has been moved or deleted” thing.

Photobucket kind of got angry or something.

The image is up now but looks terrible on my machine…
If I knew what I was doing I would try to fix it!