Moses,
Absolutely you can.
There are a couple different paths to get there. One , if you want to get the actual Bisley grips is to swap grip frames. You will want to swap hammers as well. The other is to retain the current grip frame and simply purchase oversize grip panels that are closer in size and shape to what you are looking for. I don't pretend to keep up with the plethora of variations that are available, but there are a fair number, from some makers and I am sure some of our guys can help. If not go over to the Single actions forum and they will give you all the info you could ever need.
The mid size frame that you have is really not uncomfortable for shooting loads that will stomp literally anything into the dirt. Any 270, 280, 300 grain SWC up to 1,000 FPS can be sent down the tube of that gun with ease.
