I took apart my EG awhile back to fix a loose bolt lockup issue (fixed that) and I've forgotten where a small spring goes. It's a coil spring about 1/8 inch dia. and 3/8 or so long. I was hoping one of you kind folks would give me a clue....

Found it. Firing pin inertial return spring.

Good for you! That's not one most folks get into which accounts for the huge response here...

Is that the small spring under the back of the bolt that will go zinging across the room if you're not careful?

Yup. No problems until you remove the firing pin from the bolt....

Yeah, cats love those suckers. Took 4 hours last time to find mine after I momentarily left the room. Sigh..

Got one M.I.A. right now, but bought extra's last numrich order.

I didn't know Numrich even sold cats. Mine would be MIA too if they stole a small part from my bench though.