I bought the .358 NM ZKK602 in 1972 in Smithers, B.C. from the Family Ski and Sport Shop. In 1973 I was transferred to Surrey, where I started shooting 3 position competition, using the .358 with the peep and front bead along with cast bullets.
In 1974, a Hungarian fellow, short and stocky, bought a .375 H&H BRNO ZKK602, "just for the action" to build a .505 Barnes Supreme on the action.
He had Ian Dingwll (gun smith) remove the barrel. I bought the barrel from the Hungarian fellow for $100.00 and paid Ian $25.00 I think, to remove my "old" barrel and replace it with the new one. I had wanted a .375H&H when I originally bought the .358 but none were available.
I did shoot the 280gr. Speer (or Hornady) bullets in the .358 while I was shooting it & even experimented using .30M1 Carbine cases for bullet jackets in that rifle. Never shot a big game animal with them, but did shoot a number of coyotes out on Hungry Hill.(Grouse Mountain between Smithers and Houston)Killed those dead.
I bought the Lyman mould for the .375 and used that for a year in 3 position shooting, with the peep and made "Sharpshooter" qualification (it's only the second step up the ladder)
After that, I had a real match rifle made up & got serious about 3-postion shooting.
IIRC, I used to call the Euro Stock the Humpty-back camel.

This is very close to the Euro stock design that my ZKK had as well as a similar stock now on the CZ m527's in the Eruo style.

They did get a little weird with the pistol grip, but the butt stock is where the Euro styling is.

I should note, that both of those BRNO barrels shot sub 1/2" groups off the bags, with jacketed ammo.
I used 70gr. IMR4064 in the .375 with 270gr. Hornady Spire points. That was the old "Go To" load for the H&H ctg., back in the 1970's.
Both barrels shot just barely at and odd time under 1" with cast bullets at 100yards.
The .358 was particularly accurate using 61.0gr. or 62gr. IMR3031 and 250gr. Speer bullets. They oft-times even beat 3/8" at 100. Best group for 5 shots was .251". I see that load is no longer listed in the manuals. I ran a 12X Ruko(I think it was) scope on the rifle. Cheap, but never let me down.