I've let several of my friends Fire my 500 Mag. I have noticed that more them half of them "double fire" on the first try. The fist shot is single action, and the recoil causes them to pull the trigger again. Anyone else notice this?

There can't be many of those around. Show us a pict?

It's operator error and not uncommon for first time shooters. It can be dangerous though.

There can't be many of what around? S&W 500's? I've got five of them.

DEC,
Right on! You own five 500 mags!?! One is good enough for me right now. My Dad owns an 8 3/8" barrel and is going to buy a 13".
I'm still trying to find the best bullet weight/powder charge/powder brand/bullet type for the kind of shooting I'm doing right now. Having a good time trying to figure this stuff out so far!

Sorry, thought you had to be referring to some new kind of semi-auto like a Desert Eagle .50AE regarding this "double-firing". Didn't realize it could happen with a revolver.

I would be lucky to get my 50 AE to double fire. I spend more time trying to get it unjambed than I do shooting it.