I saw .357 shotshells on one of the ammo websites. Is this shot as in shotgun? If so, what type of effective range are we talking about and what are the "Watch Outs" if any?

Yes, they use #9 shot. I've used them for plinking and mice. They can be used for snakes but I don't shoot snakes. The downsides are price and limited range.

If you could bust a clay with one I would use them by the case.

We call it snake shot, out of my 357 4", effective range about 10-15'. Haven't used them for my 45 though I don't think they'll cycle the action.

Don't waste your money unless you are shooting mice. My brother took some with him elk hunting for grouse and at 5 - 10 feet didn't even knock off feathers. We shot them at a large target at 10 feet and had about a 3 foot spread at that distance.