Try 44 special.
Try to find as many different brands, and bullet weights.
If you know someone with a reloader, or if you have one .
Load some at half powder charge what the book says, then little at a time untile your gun starts shooting better.
starting mid way of the powder charge, and increasing a little at a time will give you that sweet spot.
Clean it real good, then shoot it again.
That is how I used to work up a good shooting load.
Good luck.
jrbsr