I finally got out to a friend's farm today and proof fired this double. With the .32-20 barrels mounted it was a walk in the park. My 6.5x57R loads were 4 full grains over maximum listed. The cases showed some scuffing after extraction but nothing else and the gun is tight and on the face after 3 proof rounds through each barrel. Considering that my regulation load is the minimum listed in the Nosler manual, I'm confident that I'm good to go. Time to solder the ribs to the barrels now.