Need Help Identifying Vintage Military Helmet

hi everyone. i found this helmet last week and i've shown it to someone i know that's knowledgeable on these things but, with no luck. i'm trying to identify the origin and approximate era. this friend thought it might be Italian. the only mark i can find anywhere on it is a very small stamp "BT80". also, the way it sits in the pics, the backside(i'm pretty sure) sits up and the front side is sitting down, so it kind of looks backwards in the pics. anyway, any help here would be greatly appreciated...thanks
https://www.milsurps.com/images/impo...et_2side-1.jpg
https://www.milsurps.com/images/impo...backside-1.jpg
https://www.milsurps.com/images/impo...met_held-1.jpg
https://www.milsurps.com/images/impo...et_liner-1.jpg
https://www.milsurps.com/images/impo...met_BT80-1.jpg

I'll offer a guess. Swiss.

ya know what, i think you might be right. i'm looking at some examples online and they're awfully similar...thanks

That is a Swiss M1971...................