Joel: The real problem with people wanting to use plated shot is that they think they can fool mother nature, and get a smaller, denser pattern, at longer ranges. They can't. The reason Magnum( High Antimony) shot works so well is that the people who use it don't try to shoot it at high velocities, as they know the kick in the pants on firing is what misshapes the shot, while the plastic shot cup and collar does a pretty good job of protecting the shot from rubbing against the walls of the barrel as the shot travels on out the muzzle.
Because of the aero-dynamics of a round ball, if you want to keep a bunch of round pellets to stay closer together over a longer period of time, and hence distance, you REDUCE the velocities of the shot, and use a slower burning powder so the shot is not misshappen on ignition. With BP, you use 2Fg, or even 1Fg to accomplish this, rather than the ever popular 3Fg used in rifles. Most BP shooters understand that 3fg powder burns faster, and gives higher pressures, all other things being equal, than 2 Fg.
I am still trying to find the source of this again, but years ago, I read an inciteful article about shot pellets and patterns, where the author compared shot in the air to round balloons. He said the reader should blow up three round balloons to the approx. same diameter. In the house, so he doesn't have to put up with wind as a factor, take one balloon at a time and try to throw it as hard and fast as he can. Mark the spot on the floor where the balloon lands. Then reduce the force needed to push the balloon until you find the amount o pushing needed to make it hit the furthest away on the floor. Its usually only half to 2/3 of the speed of that " fast pitch ".
He didn't stop there. He then wrote to take 3 balloons in one hand and throw them the same amount that sent the single balloon the furthest. Mark where each of the balloons landed. Then reduce the amount of thrust until you find the speed that allows the balloons to land the closest together. This speed will be less than the speed needed to send a single balloon the furthest.
His point to this exercise is to teach shooters how air affects shot, in both slowing it down, and dispersing it, into a wider " pattern ". Those are the unchangeable Laws of Nature with which you can not fool. It does not matter if you throw balloons, or plated shot, or lead shot.
Harder shot will allow the shot to maintain its original shape better than soft shot. That is why antimony is added to the lead. Plating shot, with copper, or nickel, will help make the pellets smoother,( less wind resistance) and will give them surface strength to DELAY, but not prevent, pellet deformation when it hits a target. That is why Winchester plated shot with copper so many years ago, and developed a following of shooters who preferred to use copper plated shot in the fields. Nickel-plated shot has gotten a fad quality to it because Europeans were using the stuff in the new Intenational Trap, and Skeet competitions, that now are the Olympic style events, too. The purpose of nickel plating is not to give you tighter groups, but simply to reduce pellet deformation on ignition. However, if you up the velocity of the shell, you quickly negate any benefit of the nickel plating on shot patterns, because the AIR pushes the pellets away from each othr FASTER( Whatever goes fast, slows down fast.) The current Olympic Trap load is 3 1/4 drams equivalent of smokeless powder under 24 grams( about 4 pellets shy of 7/8 oz.) of shot, usually #7, 7 1/2, or #8. #7 shot seems to be the most popular, and actually has caused some manufacturers to beginning making this sized shot again, here in the states. Its still hard to find, and expensive.
I know of one man who has a barrel with a long choke to it, that has shot 98% patterns with the Olympic loads at 40 yds. The lighter quantity of shot( 24 grams) allows a higher velocity, while not distorting the shape of the shot at ignition. The shot gets to the target faster, before it has time to dispurse in the air. At bunker trap( Olympic style trap shooting) you stand at about 17 yds, and the shot gets to the clay target so fast, you don't want to lead the clay target very much at all. Its easier to miss if you shoot in front of one of these targets than to miss it shooting right at it. The targets are being broken at about 30 yds, and not the 40-45 yards seen in American style trap. So, those performances can mislead people to think that nickel plated shot will allow them to hold tight patterns at 50, 60, and more yards, to kill geese, ducks, and other birds. It doesn't. That 98% pattern my friend gets at 40 yds, is breaking up nicely, just like his standard American trap loads by the time it gets to 50 yds, and at 60 yds, he can't tell the difference between the two loads.
I hope this additional information helps everyone understand how to go about getting tighter patterns. Plated shot can help. But, reduce the velocity to maintain the dense shot patterns. At the ranges we hunt with shotguns, the increase in number of pellets on target will give you the edge to make a clean kill.
