doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Choke Modification Methodology ?

"Even" is a difficult word for pattern discussions. Most will interpret it as the "pegboard" distribution. Fortunately, the Rayleigh distribution is both center rich in pellets and the pellets there are the slowest spreading.

We could use "even" as follows. Assume an in-flight clay target is seen about half way between edge-on (5 sq in) and face-on (15 sq in) and exposes 10 sq in. For this presentation, one way to analize it would be to make a series of concentric "washers", each of 80 sq in. Now, divide each washer into eight "pie" sections. Count the number of pellet strikes within each "pie" section. Average all eight and you have the average number of pellets that are likely to strike a target at the average radius of the washer (aiming error). Now, compare the numbers within the pie sections. If each of the eight pie section had the same number of strikes, we could say the pattern was "even" at that radius. Repeat from center to "as far out as you care to go." Repeat for ten patterns. At this point you have some real, statistically sound data. Once you become accomplished at counting holes, you can do a pattern in about 15 minutes/2 1/2 hours per set of ten . OR, you could learn to use Dr. Jones's computerized method.

DDA

I'd be a lot higher on Jones' computer analysis if his conclusions fit what we know to be the case, based on physical evidence we can observe. Based on computer analysis, he refers to the high % of single pellet breaks that must occur in order to produce straights at skeet. The issue there is that anyone who's walked around a skeet field won't have any trouble at all finding unbroken targets with at least one hole; occasionally two. When what the computer tells you doesn't match physical evidence, it's probably time to reevaluate your computer analysis. I eagerly await Dr. Jones' analysis of what % of single pellet strikes on the skeet range do NOT result in a broken target.

Dr. Jones' analysis has two big unknowns - aiming error and %probability of single pellet strike clay target breaks. Not intending to be pedantic, but 100% minus the probability of a break is the probability of a non-break. We know that differing zones of the clay react differently to a pellet strike. We can surmise that differing sequences of the timing of pellet strikes will influence multi-pellet breaks/non-breaks. Little we know, much we don't.

Aiming error of zero would allow an infinite run of broken targets using a .22 rifle. An aiming error of two feet would result in precious few broken clays and mostly single pellet strikes at that.

Jones has given us a great start in understanding patterns and clay breaks. IMO, the method is the biggest gift of all. He has set a benchmark for scientific data.

DDA

Thanks.

The inserts are available with the holes already punched in them. Sounds like they're the ones to buy. Interesting, I wonder if the holes cause a slight oscillation of the insert when it travels or leaves the barrel, filling in the pattern hole.

Regards
Ken

Yet he makes much of his theory that there are a lot of single pellet breaks on a skeet field. I think most of us who've watched good skeet shooters, especially with the 12ga but pretty much with any gauge except maybe the .410, would say that we don't see very many breaks that look like single pellet hits. And we know from the physical evidence that it's not unusual for a single pellet strike to result in an unbroken target.

When that clay bird turns into dust and there are no visible chips falling to the ground I can reasonably say to myself that it was not a single pellet break. When I see one tiny chip fall off of a clay I think to myself, "Good chance a single pellet hit that one". Problem is, all those that I pick up on the course that have three or four holes through them with no chips gone. That is a lost bird on the scoresheet, and the only thing I tell myself that will fix it for me is centering the bird in my pattern, in the hot core. Using more open chokes is not the answer ........... for me. YMMV

SRH

these loads were fired through the same barrel at the same distance.... a mere 50 feet. They were constructed as identically as possible; the only variable being the inclusion and positioning of the Polywad disc.



The first pattern is representative of what I throw at sporting clay, FITASC, international trap and 16-yard ATA targets.

The middle pattern explains why I don't load the Polywad insert as recommended. A few patterns like that convinced me I should not use such a spreader load on live birds and most certainly never over a bird dog.

The third pattern is representative of the spreader loads I make. I load them on a MEC9000-G progressive press in normal operational mode. A standard load requires about 2-3 minutes per box of 25; the spreader adds one minute per box.

The layering method was suggested to me by Robert Harris. Author Wallace Labisky, discussed it in an article (possibly Handloader magazine?), and credited Jay Menefee, the purveyor of the Polywad discs. The focus of the article was the (then new) disc with the 3 holes in it, presumably to allow some shot to pass through and help fill the pattern voids that sometimes arise with the standard disc. Theses voids were acknowledged to occur and two possible solutions were suggested...the layering technique (which is not mentioned in the directions for use that come with the spreaders) or the new & improved disc with holes.

The void is seen in the center pic; I found it to be present in roughly 1 of 8 patterns I shot. I tried some of the discs with holes and ultimately settled on the layering technique. The use of 1/8 ounce of shot on top of the disc is purely arbitrary. The difference between zero shot on top and 1/8 ounce on top is remarkable. I surmise the post on the disc helps to keep the disc flat and perpendicular to the shot column as it travels down the bore and perhaps for a short distance after exit. This creates the maximum impedance to the shot, and more reproducibly than the cardboard overshot card that could tip and cause the "blown" patterns that Remington described in their advertising of the 1940's. Maybe the 1/8 ounce shot on top of the disc further enhances reproducibility. In any event, it seems the shot on top sees the full effect of choke and goes to the core of the pattern offering a means to modify the spread effect. Thatt raises the question of what would result by varying the quantity of shot on top...experiments I didn't pursue.

My personal use is limited to sporting clay rabbit targets inside 20 yards. It's just an idiosyncrasy of mine that I can smoke 15-yard airborne targets with my fixed IM chokes but my little pea brain won't allow me to cover up and blot out a close bouncing rabbit target. With my fixed IM chokes the spreader allows me any combination of SK/SK, SK/IM & IM/IM that I want. It also gives me the option of changing chokes in the middle of a sequence...something a choke-tube user can't do.

Mike,

I have loaded some of the Polywad inserts and tried them, in both ways, as you explained. I got the same type patterns when I tried them, and settled on the 7/8 oz. under the disc with approx. 1/8 on top. They work fine, and even though it is counter-intuitive, I still break as many close rabbits with my regular 1 oz. RIO load as I do with the spreader. So, I quit using them. I probably should give them a try again.

My question is, how do YOU divide the load? Do you use a 7/8 oz. bar to throw the bottom portion, then use a little dipper or something to put the other on top? Or, do you use a 1 oz. bar and pour a little out before adding the disc? I use a 9000G, too.

Thanks, SRH

Picture is worth a thousand words. That one shows the spreader effect perfect.

I get some "open" spots in mine too at 15-20 yards. I don't worry about it because the clay target is rarely hit square with the shot. Crosser the target moving into the shot from the side and probably going to run into pellets before it gets to the hole. If not it's still a better bet than extra full choke at that distance.

Main thing is use them for short targets and don't expect more.

Boats

Stan,

Yes, I made a dipper from a 9mm case. I normally shoot 7/8 and 1 ounce loads, practically never heavier. But once I decided I wanted a spreader specifically for rabbit targets, I experimented with a variety of components to make the perfect load. I figured a flat of spreaders might last me 10 years so I made a project of it. The main charge is tailored to perfectly fill the wad cup, which is deep enough to allow the disc to sit on top without the post touching the bottom of the cup. The upper charge is tailored to allow for perfect crimps. I've tested all the factory spreaders and I'm convinced money can't buy a comparable spreader.

After shooting sporting seriously for 20 years I finally cried uncle to silly-ass-close rabbits. Threads sufficed when I used tubes but, when I went to fixed chokes, I wanted a spreader. I don't suggest they are any better than a cylinder tube if you have them, or bare threads if you're so inclined, other than the convenience of being able to drop in a special shell. For me, they are a desperation move when I need an X, otherwise I'm happy to flail away with my tight chokes.

I drop my main shot charge and raise the handle only halfway, pausing before the shell indexer releases. Then I place a disc in the wad guide and let the drop tube seat it with a light downstroke. On the full upstroke the shell moves to the pre-crimp station with a disc seated perfectly square on top. I add 1/8 ounce with my dipper, pre-crimp and drop shot in the next in line, pausing on the upstroke again. Once I establish a rhythm, it goes faster than I can describe it.

My recipe uses a clear Fiocchi hull so I can admire my handiwork (and never chamber one by mistake)...