I havge nothing concrete accept that the cases I have seen had good prep and weiight consistency. My guess comparing it to others is Norma first guess and Lapua second guess. It is very much like the Nosler prepped from Norma.
The first lot of Sako cases I bought was back in 1977. As far as I know Sako make their own brass. It is the only company I know of that are still making
.222 Rem Mag cases. Oh, the cases I bought in 1977 were 22.250 and it was excellent brass.
A couple of years ago I asked the NZ Beretta agent if they had any plans of importing Sako ammo or cases and I received a very emphatic NO. Sako ammo is quiet popular in Australia I believe and my cousin mentioned he had seen a lot of it in the sports stores in Sweden. They use Swift, Barnes and Nosler bullets as well as their own bullet designs.