That is Bow Handle wrap. I get it from Three Rivers Archery. It's tough, does not squirm around. I have it on a couple of 65 pound long bows, and again, it's tough and stays put. All you do is peel off a layer of tape to expose the sticky side, and put it on.
On stock cracking with the Plains Pistol, other than having a very defective piece of wood, what can happen with heavy loads is that if the bolster is contacting the lock plate, that can drive the lock plate, and the cross bolt back, cracking the stock. If you make sure there is a small gap between the bolster and lock plate, it should be good to go with heavy loads.
I don't shoot the super heavy loads all the time, but I've shot them enough sighting in, and emptying the gun with no problems. When I'm packing it along with a bow-n-arrow and want serious back-up, I will load the 240 grain PA conical over 60 grains, or a round ball over 70. Recoil with those loads is "stout" and the wrap really helps keeping the pistol from rolling back too much. If I'm packing a rifle, then I find that 50 grains under either a bullet or ball is a good compromise between the really heavy loads, and the light loads.