Accuracy of Size stats on numista

Good afternoon,

my question is about sizes of the

1oz AGE and 1oz Gold buffalo.

the AGE is 90% gold and is listed at: 32.7mm, 2.83mm and weight of 33.931grams.

the 1oz gold buffalo is at: 32.7mm, 2.95mm, 31.1035grams.

so a smaller weight coin with more metals mixed in has smaller overall dimensions? This seems opposite of what i expected. With extra 10% of silver and copper the diameter and thickness should collectively be larger.

Assuming the specs are correct, its most likely due to the fact that coins are not perfect cylinders. They have a topography based on the design of each side. And the gold buffalo fairly large designs on both sides.

Two things. 

Thickness is not a specified requirement of the mint. Someone made those measurements and added them to Numista.  

Measured thickness on new coin is really the thickness of the very thin rim which extends above the details so using a perfect cylinder equation and the difference in density will not give the measured thicknesses.

There's a reason thickness is not in the Numista search engine.

OwenS

Assuming the specs are correct, its most likely due to the fact that coins are not perfect cylinders. They have a topography based on the design of each side. And the gold buffalo fairly large designs on both sides.

Why would you assume the specs are correct?

Specs from the mint: