My problem with the round butt 65 was the curve at the top of the grip. When you have recoil coming back at the top of your hand, and the fattest portion of the grip is low in your hand, there is a tendency for the gun to slide down into your hand and the bbl to flip up in the skinnier direction where you have less grip. If you've ever caught an armadillo and held it by the tail, you saw the same principle, which is a survival mechanism for the critter. The tail tapers, and when you hold the animal by it, it will thrash around and the tail slips in the direction of your weakest grip....the skinny portion of the tail. The critter slips out and runs.
What I did was use Pachmayr Decelerator grips, and at the upper rear portion, I placed a layer of epoxy, (I use Powr Poxy or J B Weld) thick at the top of the backstrap cover, and as I moved down the backstrap, made the layer thinner. This produces a wedge that fills in the skinnier upper portion of the grip and makes the backstrap vertical instead of curved. This makes the recoil more horizontal against the web of your hand, instead of squeezing downward in recoil. It also makes the bbl point more naturally and parallel to your index finger point, and you don't have to rotate your wrist downward to get the sights to align.
This does increase the length of pull on your trigger finger, so if your reach is already at its limit, this may not be practical. It is also not cosmetically attractive, but it works beautifully, and looks better if you paint it black to match the grip. You can take a file to the epoxy to get the shape and rounded sides and edges you may prefer. If you mess it up, fill it in and start over. Just be sure to make the area for the web of your hand wide enough to be comfortable in recoil. You can always adjust it with a file and sandpaper. I hope this is written clearly enough to understand.
twb