I,too am a great fan of the 1886 Winchester. I have them in many calibers, but no 50-110s at this time. I am looking for a late manufactured gun in that caliber.Some of my post 1915 guns are 33,40-82,45-70 & 45-90.These are smokeless powder guns and are have had a fairly steady diet of heavy loads with no problems.
You might contact Dave Clay in Arlington,Tx. This type of work is his specialty.My choice would be the 50-110 WCF simply because it is an original caliber and can do anything to 50AK can. Also, Starline is now making the brass and it is of excellent quality. The 71 Browning is a natural for this job as the 348WCF is based on the 50-110 case.
Dave's e-mail address is drccgs@aol.com