Unless you are a gun smith and can make a chamber reamer, how can building a 376 Steyr on a Yugo Mauser action be cheaper / lower cost than buying a used 375H&H - ie Brno 602 in 375H&H - In Australia between AUD$500 and $1000 depending on condition, scoped etc ?
If of course you have to buy a 376 Styr Reamer, again, additional cost.
Then if you take into account you need custom dies in 376 Steyr which cost a lot more thank 375H&H dies, to me it doesn't add up.