Thanks. At the moment the offered firearm is not for me, From an enquiry.

But I am personally intrigued.

Does anyone know the formula for calculating backthrust/backthrust pressure?

As the Valmets take 9.3x74R I wonder how that compares to a .375 Super or H&H Flanged or a .450/400 3" NE?

The Valmets also take a variety of medium cartridges.