8 Reales 1777 - Bad Or Not ?

Looks like a cast fake to me.

Pretty easy to see why someone thhrew it in the river.

The age of this counterfeit is perhaps 60-70 years old at most. It is an example of a casting made from a transfer die. 99% of these are of recent origin made to fool novice collectors when coin collecting began to get popular. I refer to the class as "Tourist Fakes". The more "new" collectors in the market - the more demand for cheap forgeries. The more the collectors are educated - the harder it is to pass one of these off as original.

The Contemporary castings have a different look to them because of the metal that was used and the way the dies were cast. To be successful in the colonial era a counterfeit had to have more weight than a brass casting (which is what I guess you have). Contemporary copies of castings were pewter or debased silver 60-70 percent with the surface copper removed by an acid bath.

The 1649-51 Potosi 8R are not all that hard to find, IF you're OK with sea-salvage... Many of these pieces went down on the Capitana wreck... and a good portion of what they salvaged at the time went down again on the Maravillas... So the salvage of both of those wrecks has produced a large amount of these pieces, most of what's extant.

But as to what you're getting at... Of the ones that DIDN'T sink, most were indeed melted, and accordingly NON-salvage revalued pieces are hard to find (though they're out there)... Those are the pieces on which you can often see the darker color of lower-purity silver alloy, especially when there is some environmental action involved... kind of like what the British 1920-46 .500 silver pieces look like (that "dirty" look practically from when they were new).

What's also not common are Potosi 8R from this 1649-51 scandal period WITHOUT the stamp (salvage or not).

Concerning the minors (1R, 2R) of those years... they pop up here and there... keep your eye out in the usual places (Sedwick, etc.).

I believe it was only the 4R and 8R which were revalued... The Capitana and Maravillas pieces are pretty easy to find online - like I said, they're fairly plentiful. Again, Sedwick has had several runs of them in his auctions.

There are sea-salvaged pieces that will blow your mind, how nicely they are preserved... But specifically with that 1649-51 series, if you were curious to note the debased coloration one might find on those pieces, sea corrosion and/or even slight conservation would render that hard to distinguish

You say you have a half-real transitional from 1651, not 1652? From Potosi? Are you certain about that exact date? That would be curious... Is it monogrammed or pillars style? Do you have a pic...

Oops, I meant 1652 - sorry :/
From the last Sedwick auction :

This one is actually the only half real I have for this period ...
I like those small coins (and 1/4 reales as well) - actually I like any cob :p