I do not know many top end smiths that are accuracy minded that will offer a 1/2 moa accuracy guarantee with the Wby MkV.
In talking with Shawn Carlock many years ago while we were hunting together, he had the same experience with them and does his best not to build on them. I DO NOT build on them any more.
Everyone thinks that they are amazing receivers, I am not a fan. There is no way to truly accurize one of these receivers because of the multi plane lug design. You can lap them in but its still not uncommon to see a floating lug.
Many say they are the strongest receivers out there, not really, a properly trued Rem 700 with full 100% bolt lug contact is at least as strong. A lot of what is throught about the Wby is based on opinion and myth.
Not saying they are a BAD receiver but there are much better designs out there. Plus, its very difficult to convert a Wby MkV receiver to a different case size, simply because no one at Wby believes anyone other then them are qualified to touch one of their rifles so getting parts is very difficult.
Some of the MkV rifles shoot very well, do not get me wrong, again, only around 10% simply will not hold less then 1 moa no matter what you do and as a custom rifle
builder talking to someone that will be spending potentially thousands of dollars on a custom rifle
, I will not recommend using one just because of that 10% that will not respond well to rebuilding.
It may only be 10% but when the customer has problems with his rifle, its the builder that is in trouble, not Wby and its hard to explain about the 10% after the fact, as such, I do not let myself get into that situation.
There are some builders that love them, some even specialize in them. IF you want a Wby built, I would find one of those guys.