I have had some very encouraging communication with Signore Marco Rigido, the designer of the 750 Nitroexpress and other guns and I shall post the information here along with some pictures that he has sent me. Signore Rigido has kindly agreed to give information on several of his future projects, so please watch this space. His website is http://newsystemarms.com/new-system-arms.php?language=2

The details of the 750 NE rifles are:

Express gauge 750 Nitro

Express is the biggest gun in the world made by Sandro Lucchini.
It's an unique example for beauty, difficulties in construction and refined
performance.

Cal. 750 N.E.

Double express

holland & holland type

barrel length mm. 720

price euri 300.000

ammunition date

cal.750 Nitro Express

Case type rimmed strainght,

length case mm.89,5

head diameter mm. 20,27

rim diameter mm, 24

bullet length total mm.

diameter mm.19 . 1.300 grains

velocity 2020 / 2129 ft. 650 m. s.

Good hunting, everyone!