I?m not surprised your arms ache if you stand there, gun at the ready, from the moment the drive starts to the second it finishes.
You need to lighten up a little, and relax! Take the strain out of the day by either resting the gun over your forearm or by holding the grip of the stock with the barrels against your shoulder.
The first approach means the barrels will be pointing safely at the ground while waiting for a bird to come your way, or harmlessly into the sky if you prefer the other option.
Whichever you choose, it?s then an easy thing to bring the gun to the ready position ie muzzles on the bird, gun butt slightly forward and just below the armpit.
From here you can now move your feet easily should the bird look as if it?s going to pass to your left or right.
As soon as you move into position the gun mount proper can begin ? a simple affair because keeping the butt just below the armpit means you now only have to lift the gun a short distance to the shoulder pocket.
From adopting the ready position to shifting your feet, mounting the gun and firing takes only a few moments ? and done properly the whole thing appears to be just one movement.
A few minutes spent dry mounting at home will soon have you going through the sequence smoothly and automatically. Try it!