Mark 10 Mauser. I don't know who made them, no thumb groove and commercially sold actions and rifles. I have one on my .375/06IMP. It's an excellent M98 action, standard length.

just googled it- Interarms

https://www.google.ca/search?q=mark+10+m...4ylDozkjgTUw4pg

One of the posts on a different forum:

"They are made by Zastava, but the Interarms guns were much more highly finished than the Zastava's currently being imported as Remington 798's. I had one in 458 Win Mag and it was a slick gun and very accurate."

I must add to this - the Mark 10 Mauser actions are quite highly finished, like a Browning FN action.