I have a SRH in 44. The only thing I have taken with it so far is a fierce woodchuck on a full charge at 18 yards!!
I droped him in his tracks with a Remington 240gr SJHP.
I would look at the Hornady XTP. Seems like the last I bought was $15 for 100 of the 240gr pills. The XTP is a great bullet.
I would try Badger Custom Grips. He has grips listed for the GP 100, I do belive thats close to the same grip as the SRH. Give Jim a call and see. I like the looks of the finger groove grips. Here is the link.
Badger Grips