One thing to keep in mind with temp guns - all but the Exergen are emission reading devices. Displayed temp readings can be influenced by color of the cooling head and also the porosity of the head.

When testing, put a piece of duct tape (colored similar to the engine head) on the outside of the pan of hot water and take your reading on the tape. Not perfect, but better than taking a reading through water into a shiny bottom pot.

Ah, thanks for the tip on testing my temp gun. On a boiling pot of water right now it was reading about 208F, that's about right on, just a few degrees off. Thanks again.