I asked them about the 135Gr SB bullet and they told me that it was designed for "Short Barrel" guns with velositys just over 1,000fps to 800fps,for best results.
At higher velositys the bullet might have a tendancy to seperate or have the copper pedals break off. If velositys are over 1,000fps they said the 125 Gold Dot would be the correct bullet to use,due to the heavier construction makeup.
Note:
I tried a 125 GD in my snuby at "Nyclad" velositys, this one was doing 836fps at 8 feet and went through 3 water jugs and 3/4" into a partical board. Picture to follow.......