Now I'm confused again. The more I learn the less I know.
Up until recently I thaught the general opinion was that the advent of plastic shot cups revolutionized shot gun patterns. The standard chokes of M/F 75 years ago changed to I/M because of tighter patterns with plastic. Some gun writers tried to convince us that chokes in a shotguns aren't even necessary any more. Now I'm being told that at normal ranges it really doesn't make a difference.
Is there a simple explanation? I guess there usually isn't.
There are many different sizes and shapes of forcing cones. We hear about the benefits of certain forcing cones for trap use, target use, lower recoil, higher velocity, etc. In fact, nearly every manufacturer's forcing cone design is a bit different than the others. Granting that various forcing cone shapes offer whatever advantages are claimed, the issue of wads becomes primarily one of providing a good gas seal in the forcing cone and barrel, and secondly one of buffering the shock of the load going from zero fps to 1200 fps in a fraction of a second.
In "the olden days" fiber wads made of tough natural fibers, usually wool felt, often didn't expand enough under pressure to provide a good gas seal through the varying diameter of a forcing cone. A hard card was used to separate the powder from the wad but it was not uncommon for shooters to find some of their pellets were fused together by hot gasses leaking into the shot column. Clumps of two, three, or more pellets just don't pattern or fly very well. To mitigate the problem, forcing cone designs tended to be short by today's standards and the concept of "over bore" was not popular. Loading with multiple wads also helped. For, example, in the 1930's Stoeger listed "white felt", "black edge", "pink edge", "nitro felt", "grease proof", and "seal-tite composition" wads and recommended them to be used in various combinations. They were also offered in "one-half gauges, cut to order".
Then plastic wads came along. They were advertised by their manufacturers as the panacea for all problems with shot, pressure, and patterning. In general, plastic wads have a flared base that expands under pressure and helps prevent the flow of hot gasses into the shot column. The flared base maintains a decent seal regardless of the shape and length of the forcing cone. Built in "buffers" are incorporated into the design to reduce deformation caused when pellets smash against pellets when the load is fired. Today, there are dozens of different configurations of plastic wads, all touted as better than the competition's. Some of the designs are so bizarre that they must surely have been developed with the sole purpose of having something new and different to introduce into the marketplace.
Good quality fiber wads of today are not the same as the simple felt wads of the past. They are thicker and are made with a mixture of man-made and natural materials. I just cut a top quality 12 gauge cartridge open and here is what I found. Over the powder was a very hard card more than 1/8" thick that is fully impregnated with a waxy substance. On top of that was a fiber wad nearly 3/4" thick. The fiber wad has a black film of some plastic-like material bonded on each end. The wad itself consists of numerous layers of "fiber" compressed together. I have noticed when firing these that, unlike felt wads, they disintegrate when they leave the barrel. I don't know if it is the plastic film, the composition of the fiber, the diameter, the long length, or all of it together but whatever it is, it works. I have fired modern fiber loads in 12, 20, and 28 gauge in new and old pump guns, several autos, several doubles, and two single barrel trap guns. I also chronographed and patterned a dozen 12 gauge shotgun cartridges, some with fiber wads and some with plastic wads. I fired several of each of the tested loads out of an auto, a modern O/U, and a 100 year old SxS. I did not find any significant downrange difference between good quality modern loads with fiber wads and good quality modern loads with plastic wads.
