I had a 7mm Weatherby Mark V Ultra Lightweight for a while. The 1-10 twist shot fine with the 175 Hornady Spire Point here in Montana at 4000 feet above sea level at typical fall hunting temperature of 35 degrees. Also saw my companion's Mark V work fine on a bull elk at 8500 feet in Colorado, with the same bullet.
I used the 160 Partition in my rifle for hunting, which shot very well at around 3200 fps.
In general, I haven't found the Weatherby freebore to work all that well with high-BC boattails, but can't say that's a hard and fast rule.
