There is also the fact that patterns deteriorate at an exponential rate and though their 'silhouettes' may be similar in shape they will not be in density at any significant similar distance from the muzzle. Speaking here of differing charge weights of same size shot. Nonetheless, there should be a point [distance from the muzzle] that pattern effectiveness is similar from one gauge to another though they will be dif from one to another in distance. That is the comparitive 'sweet spot' or equality point that you are referring to.
I do not think it is any more easily arrived at mathematically than a pattern can be forecast. That random behaviour within parameters [observed limits?] is always going to remain proximate, rather than exact.
The likely reason there is no such chart existent is that the nature of the problem is not wholly linear. Lest I have confused anyone, I do not argue your thinking at all, Stan. However, aside from some extensive empirical pattern testing with the specific loads & guns you might wish to use, knowing the exact range where that 'sameness' exists for both guns & loads would at best be a SWAG. And then what are the odds of encountering game or target at the exact desired range?!
It is much easier to simply limit shots taken with <3/4oz. payloads to inside 30 yards & use shot of sufficient size for the intended target. 3/4 oz. payloads [not only in 28's, but 20's & 12's too] can & do put mourning dove & other upland birds in the bag & break bunker targets at ranges of 35yards + with what would seem disportionate regularity. Brister was quite intrigued with that observation in regards to the 28 ga. & went to some length to find out why it was the case & wrote a book on the subject. Was it difinitive or absolute? Yes & no. It did shed a lot of then new & interesting light on the quest for an answer. He did not, that I recall, ever ask nor speak to your observation.
I'd call it an observation more than a question and a valid one, but I have no expectation of seeing an equivalence chart of assorted gauges vs. range anytime soon, though I guess someone might play with it on an X/Y axis using a linear regression from a lot of testing & data points & come up with a rule of thumb kinda thing. Not sure what one would do with it if it existed.
No doubt, you could likely publish your findings in an article of interest as Sherman Bell has done. I dunno whether I'd call it a potential hornet's nest, a pinata or a can o' worms;-);-)The validity of your observation is real enough, however the proof in any absolute graphic is problematic.
Best, tw
Last edited by tw; 03/07/13 02:18 PM. Reason: changed the word 'footprint' to 'silhouette' for better clarification
