You have understood what I meant and I apologize for my bad English but I speak solotanto Italian and French, and what I write is the result of google translate translation.
what you say is not correct in my view, the 70xx class aluminums are more resistant to shocks (and therefore harder) than the 60xx class but always alluinio you are talking about and the differences both in physical terms (just as an example the specific weight of 7075 is of 2.81 gr./cm3, the specific gravity of 6061 is 2.70 gr./cm3) that workability with cnc machines … are very limited and the minimum thickness at which we you can push it virtually ugule for both (I have a manual lathe and then I tell you from personal experience).
The first example that comes to mind is the Draupnir and Invaders must die … same specs, same weight (0.5 g more per second) but with different aluminums virtually identical specific weights … virtually even thickness very similar.
Another example is the copy of Sleipnir we were talking about, if it weighs less than two grams must have less material and therefore more original thickness is reduced in 7075
I enclose this table with the physical characteristics of some of the aluminum alloys among the most used, but it is in Italian (I can not find it in English)
http://www.airoldimetalli.it/fileUpload/39_tabelle_di__comparazione_barre.pdf