Don, let me suggest a couple problems with pattern analysis relative to skeet:
First, skeet targets are all relatively close range. 25 yards would be a pretty long shot. However, a lot of targets are shot much closer than that. Even with a .410 and half an ounce of shot, you can smoke station 8 birds, and the incomers on 1 and 7 in particular. Especially on doubles, when they're going to be fairly close. So if you're analyzing patterns shot at an "average" distance, there will in fact be some birds taken much closer than the average. Therefore more likely to be hit by more pellets than represented by patterns analyzed at an "average" range.
Second, a pattern is a two dimensional representation of a 3 dimensional phenomenon. Even if the holes in the paper look like they're spread enough in two dimensions that only X number will strike the target, it's possible--due to string--that either more pellets (or, for that matter, fewer) will actually hit the target close enough together in time as well as in space to influence the break. I don't believe string is a really significant element at skeet ranges, although Brister does point out that good skeet shooters, who are more likely to miss ahead than behind, can benefit from string on crossing birds when tail-end pellets compensate for excess forward allowance.
Finally, it's difficult to compare 100 straights today with 100 straights when skeet was a new game. The old rules required low gun and a variable delay of up to 3 seconds. When those 2 factors were eliminated, American skeet became a mounted gun game in which a shooter can refuse a target because of a slow or fast pull. 100 straights became far more common. If you want a bit of entertainment, watch modern day skeet shooters attempt to adjust to skeet under the original rules. As far as chokes go, the game was invented by grouse hunters, who already were shooting pretty open chokes. And all the major gunmakers were producing purpose-built skeet guns, years before WWII, with open chokes. So I'd say it was more a case of the rules making 100 straights rare rather than the chokes.
