As is probably obvious, I am new to the forum and have not yet figured the ins and outs of responses, quotes, etc. That said, I thought I had already responded to one inquiry, but I do not see my response. Please forgive my repetition in the event that my response appears.

First of all, my sincerest thanks for the warm welcome and the multiple useful responses to my inquiry. Now, allow me to elaborate on the situation in question.

My work often puts me at odds with angry animals, such as broncs that object to being ridden, or bovine beasts of short temper and shorter patience. On the occasion in question, I happened upon a 1000lbs+ steer whose life goals differed from those I had for him. Understandably, he reacted violently. My horse, being much more educated in the ways of unreasonable cattle than I, saved us from certain injury and significant hospital bills. Unfortunately, in spite of my good horse's gallant agility, the beast needed put down before our luck ran out. The steer absorbed two 260gr #429421s in front of 7.7gr Unique, one behind the left shoulder and another in the brisket. We finally put him own with a third in the forehead. Penetration was adequate, but no bullet exited. Granted, this was indeed a unique situation and is by no means a normal occurrence.
Admittedly, this pistol and this load has been more than adequate for anything I've asked of it through my day-to-day central Oklahoma duties, and I am not ready to depart with it. However, I feel I owe it to any future angry steer, (and Smith&Wesson) to at the very least satisfy a curious itch, and perhaps allow increased velocity and a bit more of a punch to make up for my poor horseback pistol work.
For those of you questioning this load in this part of the country, your skepticism is valid. Had I been a better shot on a moving horse, it would have done it's job. Perhaps more practice is needed as opposed to a caliber/pistol switch.

Thanks again for your participation, all.