Overweight 5kopeks - common or rare?

I have a 1769 5kopek coin, but it's weight is 76.4 grams! Not 40-50grams.
Thickness of the coin is at least 5.5-6mm.
Rare? Common? Or counterfeit?

Not rare off corse. It's not overweight.

The weight differs because at that time there was no weight control over a single coin struck in the mint. Usually mintmasters weighted lots containing a number of coins. If the lot was way less than decreed - the thick coin(s) was added to the lot. This could be a legend, of course, since the coin disks production was not perfect - that might happen occasionally.

Not a rare piece.

Ну, бляха, я и сказанул ) сам себя не похвалишь, никто не похвалит.

Ah, interesting.

But is there a reason why I don't see so many of these overweight coins on auctions?

Ah, interesting.

But is there a reason why I don't see so many of these overweight coins on auctions?

Do You know the weight of each one copper 5-copecs pcs, which do You have?

I"m not..

If coin will have a double or half of weight - its will be noticed...

But difference from 35 to 70 grams - almost common... And nobody is interesting in..

Ah, interesting.

But is there a reason why I don't see so many of these overweight coins on auctions?

Cause anyway double weight coins were not standard. Law said that 16 roubles (1 "pood") in copper coins must weigh 16 kilos of copper. Try to get 16 kilos of 5 kopeck coins and you will have anything: half weight and double weight.

Besides I guess you don't see many of these on auctions since nobody notes the weight.

Ah, interesting.

But is there a reason why I don't see so many of these overweight coins on auctions?

Do You know the weight of each one copper 5-copecs pcs, which do You have?

I"m not..

If coin will have a double or half of weight - its will be noticed...

But difference from 35 to 70 grams - almost common... And nobody is interesting in..

Basilio is right. I just noted that you a comparing a standard ("overweight") coin with Paul 1 re-strike coin (which is and must be thinner). Your correct question should be "why the other coin is thinner and have bigger diameter" ))

No, my other coin is overstriked, so I can understand that the diameter is bigger. I have seen more than 5 kopek coins, but I don't think I have come across anything more than 60 grams.

Most of my 5 kopck coins are around 45-53 grams, but nothing like 76.4... 76.4grams is almost the weight of 2 underweighted 5kopek coins.

No, my other coin is overstriked, so I can understand that the diameter is bigger. I have seen more than 5 kopek coins, but I don't think I have come across anything more than 60 grams.

Most of my 5 kopck coins are around 45-53 grams, but nothing like 76.4... 76.4grams is almost the weight of 2 underweighted 5kopek coins.

Again, I'm affraid, it is pointless to consider seriously the weight of each individual coin of 18th cent. Even gold and silver coins of that time can differ remarkably (up to 50% in my experience). Nobody regulated weight of coins piece by piece, only by lots. Usually catalog indications of weight are merely result of division of legally stated weight unit (pood, pound etc) by amount in roubles & kopeck which had to be stroke out of that weight.