Hi SkiWhiz,
The heat is not too bad...but we sure need rain really badly...not just to soften the ground to dig, but where I am, trees are dying and dropping limbs in attempt to stay alive....
I've found the Omega to be fantastic on silver, both coins and rings...it also hits of medium sized gold rings really well, and locks on to the numbers.
On deep targets (8" +) Ive found that the visual ID does not lock on so well, but with a bit of use, you can get to look for the tell-tale signs of it being a silver coin...i.e. hitting the approximate correct number from time to time, or even when you first hit the target...at shallower depths it usually locks on pretty well...depending on the mineralization of the soil, the number may not be exactly what you expect, but pretty close. I have also found many silver chains and bracelets with the Omega....usually ID numbers that are a little low for silver, but the audio tells you to "dig". Last year I found 144 of our old silver coins (pre-decimal), from 3rd through to Florins, and by far, most of them were found with the Omega. I found 15 silver coins with the Eurotek Pro, so it did ok too.
The Eurotek Pro is also good on silver, and whilst I have not found the numbers of finds with it that I have with the Omega, I have not used it nearly as much as I have the Omega. I find it to be a very competent machine, and some of its features are great for some of the places I detect. I have not used the Gamma, so cant comment on it, but I'm sure there are some reports on it on the forum. Best of luck, Pete