Well, loading for the single six is kind of a no-mans-land deal as far as I can tell. The SAAMI max for the 32 H&R is only 21,000 CUP. With a 120 gr. bullet you're not looking at much more than 1000 fps out of a short barrelled revolver. Figure the factory load is a 90gr. bullet at what, 1100 fps? But we all know the 32 H&R can be significantly hotrodded in the Contender. There's basically nothing you're going to load it with that will hurt a Contender. But a single six? Hard to say. The cylinders aren't very large in diameter, and the 32 chambering removes quite a bit of metal. I'm sure the load you're using is safe enough, but I have my doubts as to the longetivity of a single six shooting a steady diet of them. I don't know anybody who has shot one enough to know for certain, I may be way off base but I don't push my SS that hard. The contender is another matter, it's easy to get 155gr. cast bullets to 1500 fps with it using a 10 inch barrel.