Does anyone own a Ruger No.1 in this caliber?

Would that be the 338 version of the 33 Poacher's Pet?

I've not heard of that wildcat before, so I'm afraid I cannot be of any service. The 338-74 Keith is the 9.3x74R necked down to .338 and the case is "improved" a bit. It was Elmer Keith's wildcat.

if it were me, I would just type in www.CH4D.com and select 338 caliber. It's on page 2 for $119 plus shipping. They also make the reamer.

Rich