I have a 11.15x47r and have used 9.5x47r brass from Bertram and have also used 45/70 brass. For my rifle, I was able to use 11.15x60 dies with a smiggen grounded off the bottom.

As Sharps said, the x47R brass is based upon the old military cartridge 11.15x60r which has a Mauser A head. The Mauser A head is a thick head, much thicker than a 45/70.

To form the case, I simply ran a lubed 45/70 case into the dies. However, as noted above, the Mauser A head is much thicker so the head of the reformed 45/70 case must be modified.

There are two approaches. One is adding a wire ring to the back side if the refrmed case rim and people normally make these from piano wire.

The second approach is to thinken the rim by placing the case on a vice flat and tapping the rim forward (away from the primer pocket). I used this method and cases work well.

Going off recollection, I believe I used 50 gr 2F and a 386 gr bullet. I also used 22 gr of 4198 and the 386 bullet. I also used lighter bullets.

Best success with your rifle.