doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Pattern theory

Larry, I think a bigger factor is you don't have so many pellets on the bottom to run into the upper ones. The front ones draft the rear ones but slow rapidly, letting the rear crash into those ahead. With shot collars bore deformation is a small factor.

You are exactly right, Joe, about shot collars (cups) and shot deformation.

SRH

Afraid I must disagree a bit. All patterns will have a Rayleigh distribution (the Rayleigh distribution is, indeed, a Gausian distribution, one of several). That distribution will hold from muzzle until the shot hits the ground. There is no such thing as "uniform" in a pattern. There is no core, either. The highest concentration ( pellets per square inch) of pellets will be at the center and will "taper off" (although not a linear taper) as you move away from the center. As the pattern travels away from the muzzle, the shot "feeds" away from the center toward the edges such that the Rayleigh distribution is maintained. % in some size circle is OK to compare one pattern to another for choke effect, but tells you little about the actual pattern. "Better" is the pattern with the largest diameter of lethal dose within your targets square inch area.

You will likely be able to tell difference among bore sizes of equal choke as they will have slightly lower choke effect for smaller diameters. Larger diameters will be able to achieve slightly "fuller" choke effect.

I have to disagree on shot drafting and crashing into each other. The wakes of those tiny lill' spheres are going to be very turbulent and I do doubt one being able to follow another for any but a very short time/distance.

DDA

Not all shotgun patterns adhere to the theoretical model.

These 3 patterns were shot with the exact same number of pellets, through the same, fixed-choke barrel at a distance of 50 feet.

IMO, one is better than the other 2.

Ok Mike, you must now reveal to us the variable that resulted in such significant pattern differences.

I'm guessing the middle one is a factory Polywad SpredR; the right one maybe a Mike Campbell spreader reload.

If you pattern from different loads/guns etc even if all put the ame percentage of shot in the 30" circle, you will find if you then draw a circle containing half the area (21.2") concentric with the 30" circle they will not all have the same percentage inside that central area.
Another factor other than bore scrub is an ounce of shot will have a column length in an unprotected bore of about .690" in 12ga, .837" in 16ga & .970" in 20ga. Thus the lower pellets in the column have a heavier load to move upon firing. The reduced diameter by use of a shot cup will of course lengthen these columns proportionately.
The column lengths cited were from old Hercules/alliant loading guides. They did not state the size shot or the hardness. Both would have an input on the exact length, but as long as the shot was consistent it would vary proportionately. As I stated earlier I have not counted enough pellet holes to say positively just what effect the actual bore size has on pattern but I do know that not all patterns have the exact same central thickening.
People who concentrate on extreme long range shooting consider central thickening an advantage, most of us consider it a disadvantage & prefer to lessen it as much as is possible.
My personal opinion is this is most apt to occur with the shorter columns of a bigger bore.

Couple of years ago the FITASC shooters had to go from 1 1/4oz of shot to 1oz. Most bitched about what it would do to scores. The scores stayed the same. International games only allow 7/8oz of shot. And I've read a couple of articles in SC's magazines about how 3/4oz of shot patterns. In one the man claimed at skeet ranges the pattern was too tight unless the velocity was upped to 1300fps or fiber wads were used. Mike, was the velocity or wads changed ?

Mike, while your patterns are not part of the original question or theory they are quite interesting, and show the ability to change patterns and chokes in a fixed choke gun by load manipulation. Please share how this was accomplished.

I'd be like totally fascinated to know WTF that is supposed to mean? And which particular Hogwarts Physics theorem is employed?

And there is seemingly a confusion between choke as marked, choke in thou of an inch, choke as % of bore dia, and most importantly choke as in performance. Y'all might want to pick one so all y'all are talking about the same thing. And you might want to give a look at Neil's methodology and actual analysis for some clues about how to present whatever "data" you come up with.

just thot

have another day
Dr.WtS

I have to admit that topics like this on this forum are among the most amusing to be found anywhere tho the trapshooters and shotgunworld press hard for top spot. Keep up the good work!!