It's on the official archeological publish of the discovery of Tintignac. I also had access to a web site with 3D modeling but it's no longer available.
Here is the paper : www.researchgate.net/publication/329233917_Le_carnyx_et_le_casque-oiseau_celtiques_de_Tintignac_Naves-Correze_Description_et_etude_technologique_Dossier_Tintignac
