(Image removed from quote.)

Edit: Now lets see one with a .50. 
I don't know how to post pictures, but go to
www.cybermodeler.com/armor/m4/m4_gallery.shtml and look at the bottom row of pictures. The pictures are labeled as M4's and by the looks of the main gun its a Firefly. I have no idea when the pictures were taken.
Bronk, you are starting to take this a bit personal. I made the following statement in an earlier post
"To be honest with you I would settle for a 50 cal on the tanks, at least we would have some chance of defending ourselves.". I never said they did, but when I was told they didn't, just our of curiosity, I did a simple Google search, and in Wiki, two different sites stated they did. Now you come back wanting me to prove that they did, when in fact you have not showed any sources, other than a couple of pictures, that they didn't.
I clearly stated that I am not a WW2 expert in anything. I just did a simple search out of curiosity. I then get told that my source is inaccurate. I was asked to find a picture, and I think I did. I'm not really sure, because I can hardly tell one tank from another, but the picture is labeled an M4 and the gun sure looks like a Firefly's gun, and I am pretty sure thats a .50 on top.
Bronk it sure looks like your wanting to start something out of nothing, and I have grown tired of this subject. This will be my final post, right or wrong. I will concede to you they didn't mount 50's on Fireflys, because for the most part I really don't care. I was just a bit bored this morning, and played around on the Internet a bit.

Fred