No- just .375. We've built 2 of them. 3,100fps with 235's and 2,900fps with 270's when using RWS brass. I suspect the pressures were running in the 65,000 to 68,000psi range- just a feeling, no definite data, but no problems of any sort and with brass lasting over 30 firings. Even the re-worked .375H&H brass lasted over 20 shots. Make them fit first and they go on and on.

.375H&H brass - turn belts to .522" (from .532") - neck up to .400, size to .375, trim to length and fireform. Easy!

I made my own dies, Keith had RCBS make him a set, called 9.5x68.

It would make a good .416, of course, but the .416Ruger already is there with a couple gr. more capacity and straighter case walls. Either/or - pretty much identical ballistics - 1 factory, 1 wildcat. I prefer wildcats - more fun.