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devrep Offline OP
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I'm sure ya'll have discussed this. another post got me looking at photos of some of my guns and some of the photos are of patterns I shot a few years ago. most of the patterns shot do not match the choke measurements as to what is commonly listed on choke charts.

for instance, I have a superposed 410 skeet that at 30 yrds patterned mod/full as far as percentage of shot in the circle.

28ga super with Simmons barrels measured at .001/.001 patters IM/full.

Parker VH 20ga measures .014/.006 but patterns full/full.

Uggie 410 marked IM/mod patterns full/full.

Belgian 28ga sxs measures .010/.011 but patterns IM/IM.

Model 21 12ga measures .010/.032 patterns mod/full.


I have 2 Superposed 12ga trap guns that are full/extra full and pattern perfectly.

Is this a result of modern shells with shot cups and choke charts being out of date?

Last edited by devrep; 11/28/12 12:18 PM.
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It's nothing more than a situation where barrels are stamped based on dimensional considerations rather than performance with any individual load.

No big whoop there. Same as it ever was.

HTH

have a day

Dr.WtS


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Originally Posted By: devrep
Is this a result of modern shells with shot cups and choke charts being out of date?


GT Garwood / Gough Thomas wrote that in his opinion the shot cup tightened the pattern one degree of choke. I took that to mean that half choke shot as a 3/4 choke and 3/4 choke as full. He wrote that in the 1960s I believe.

And certainly not all barrels choked 20/1000ths shot the same patten density, as in your mileage may vary.


Best,

Mike

Last edited by AmarilloMike; 11/28/12 03:27 PM.


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Even farther removed from serving as an accurate predictor of performance is the "choke" stamping on the barrel.

I can understand how someone might not spring for a bore gauge. Believing a specified choke stamping obviates a need to pattern with one's chosen shell is inexcusably naive.

Sam

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Originally Posted By: Wonko the Sane
It's nothing more than a situation where barrels are stamped based on dimensional considerations rather than performance with any individual load.

No big whoop there. Same as it ever was.

HTH

have a day

Dr.WtS



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Originally Posted By: devrep
Parker VH 20ga measures .014/.006 but patterns full/full.


No slight intended, but if you can't see a difference between those two chokes in that gun, I'm somewhat suspicious of your testing protocol. Just sayin'.



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Lovely responses. Choke is empirical as well as shot size dependent. There is no substitute no matter what any one person might say. I guess choke vs. constriction might be interjected.

Kind Regards,

Raimey
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For those who have considered the idea or rejected the idea, I strongly suggest reading Dr. A. C. Jones's book on sporting shotgun performance. Per Dr. Jones, it takes 10 patterns statistically analized to say much about any given barrel-load combination. The problem is that there is so much shot-to-shot variation that a single pattern is pretty much worthless as a predictor of barrel-load performance. Likewise, eyeball analysis is not reliable. He offers a nifty bit of software that will convert digital photos of patterns into statistical terms and values. BTW, to date, choke constriction is the only predictor of choke effect. Most of what we have read and been told has been based on far to little data.

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+1 on Dr. Jones' book. Not exactly breezy reading, but very informative on various shot performance issues that are often the victim of wives tales.

I was helping a friend gunshop for a target gun (hey, someone's gotta step up) and came across a post elsewhere on Beretta's new DT11 and its "Steelium" barrels - according to Beretta "The result is the creation of a progressive conicity that removes any sudden constriction, allowing the DT11 to fix new performance standards."

The poster was commenting on how the IC choke on his DT11 was delivering "hard breaks" at 40+ yards, which has to mean that the IC choke was probably delivering Mod/IMod choke performance (something like 70% at 30 or 35 yards). Which is all well and good, but the poster clearly did not recognize that there had to be a trade-off - that "IC" pattern must be ~10" smaller at 25 yards than a true IC choke in order to deliver that performance at 40 yards.

Interesting how gun makers and shell manufacturers never offer pattern testing to back up their claims of "improved patterns" and "improved shot concentration and distribution." It also makes you wonder if any pattern testing happens to confirm performance, or do they just thrown in a box of .005, .010, 0.20, .025 and .035 chokes with the standard markings and consider the job done.


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devrep Offline OP
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perhaps you are correct. I used a 30" circle at 30 yards for the 20 ga. This was years ago, I'll have to get the bore gauge out and see if I made a mistake in measuring. don't think so though.






Originally Posted By: mike campbell
Originally Posted By: devrep
Parker VH 20ga measures .014/.006 but patterns full/full.


No slight intended, but if you can't see a difference between those two chokes in that gun, I'm somewhat suspicious of your testing protocol. Just sayin'.


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