What is this shell?

[jay29]

I found a pic of it on the net, but with no description:

An Introduction to Collecting Artillery Shells

Look at figure 13, left hand pic. On that pic, it would be the small one on the right. That looks exactly like the one I have, but mine is fired. What do you think it is?

Thanks,
Jason

 

[Gspragge]

37mm

looks like an M51 type, but something is missing, a ballistic cap or some such. Can you make out any remaining markings on the band.