273 Round can Lake city AP

Anyone seen one like this? Anyone know the history?

https://www.milsurps.com/images/impo...Fi8hjpg1-1.jpg

On first glance, looks like a repacked box of 273 rounds of .30 M2 AP. Used to get all kinds of repacks when ordering for use in the foreign arms ranges. Layer pack is unusual to me.

273 is a good, round (so to speak) number!