Hugh,
I have been a hand loader for 30 years. The test load technique described by S.B. was shown to me by a retired gentleman that long ago. Like S.B., I had a rifle that would not accurately shoot factory ammo. Using hand loaded ammo that was tuned to that rifle, it delivered groups just over 1 inch at 100 yards. I’ve used hundreds of these loads over time. When I pull the trigger I expect that round to go off as planned. I expect the bullet to land very near where the crosshairs were when the gun went off. By the way, that technique can be used for any cartridge and component combo to optimize accuracy.
I also can tweak any given round to tilt the results. One load uses ultra sleek bullets with a high energy propellant to ‘deliver the mail’ at long range. I also make low cost practice and small game rounds that use cast lead or copper plated bullets and a small amount of propellant yet still deliver good accuracy. I pick an application and develop a load that fills that application.
For instance, like most folks my shotgun has a single barrel. I use hand loads to expand my effectiveness. Spreader loads open the pattern for that first close shot. The next shot is a standard type that delivers the standard range pattern as controlled by the choke. The third shot is a load assembled to deliver a tighter pattern. Three shots, three different patterns, and all are from a single barrel shotgun.
I can better control costs. Components are available in bulk. Just like comparing the cost of a single roll of paper towel from a convenience store versus a huge bulk pack of paper towel from Costco. You pay more for the bulk pack, but the cost per roll is much less.
Lastly, an important safety tip. Get your data from legitimate sources. That gun is going off in your hands, in front of your face. Safety first! – T.J.Away