I am primarily into shooting 16-yard line and 27 yard line trap. I get on the targets fast,at a braking range of 27-32 total. 27 yard line would be at 38-43 yards out.
What would be the best choke diameter for a quick shooter? Also would would be the most open choke possible for 16 yard line that would reliably brake the targets? I use .20 for 16yard line and .30 for 27 yard handicap. Also i use 8 shot from 16 and 7.5 for 27 yard birds.
It is really hard to discuss choke diameters or choke names when you are trying to describe an exact choke performance. It sounds as though your 16 yard choke is a standard “modified”. The normal constriction of a modified is right around .020″, which you have. That said, the definition of a modified pattern is 60% into a 30″ circle at 40 yards with the shot load in question. IF your .020″ produces that pattern with the load of #8s you are using, then and only then do you have a true modified choke. Just because the choke mikes .020″ doesn’t mean that it will throw those 60% pattern with the shell you are using. But, you probably know all that anyway.
Is a true 60% modified pattern of #8s ideal for a 30 yard target? Technically, I think that it is. This is assuming, of course, that you are using the full 1-1/8 oz of shot permitted by the ATA. I won’t even discuss shot patterns with less than all that the law allows.
Rather than stipulating it all in terms of pattern at 40 yards, it might be more helpful if you considered it in terms of 30 yards, about your average 16 yard breaking distance. To maximize your 461 pellet spread on a target exposing about 8.5 square inches of surface, you are going to want about 80% of your pattern in a 30″ circle at that 30 yards. If your .020″ choke gives you that performance, then you have the right choke.
Now here’s what is interesting. While an 80% pattern in a 30″ circle at 30 yards is the ideal pattern percentage for a trap target using 1-1/8 oz of #8s, any pattern percentage between 65% and 95% at that distance is very, very close to being just as good. The difference is only about 1/2″ of killing pattern (24″ vs 23+”).
The professional trap shooters realize this and this might explain why so many of them use only one gun (full choke) for 16 yard AND handicap.
As to you handicap choke, trust me on this, use everything you can get in your gun no matter how fast you shoot. All the formulae available indicate that your pattern maxes out right around 80% to 88% with a 22″ killing pattern to a fringe which offers an (80% chance of two pellet strike.
Let’s say that you are breaking your handicap birds at an average 40 yards (38-43 as you say). To optimize your chances on a slightly turned 110 mm target using 1-1/8 oz of #7-1/2s, you are going to have to put around 85% of those pellets into a 30″ circle at that 40 yards. This is definitely Extra Full choke territory and I would start to experiment with something in the .040″ constriction area. .030″ is quite unlikely to produce the density that you need unless you have an exceptional barrel.
This is a good place to mention that I am not a mathematician. Far, far from it. I do get my stuff from real mathematicians though. Mathematics guru Warren Johnson sells a most excellent “Choke Chooser” slide card. It is based on a proper Gaussian pattern formula. I also use another program, still in its experimental state, from a recognized expert. I can’t vouch for the math, but I can vouch for the fact that the results jibe with my personal experience and observation.
Contrary to what people tell you, when the bird is edge-on or nearly so, you are definitely better off over choking than under choking. Remember, ALL shot patterns are denser at the center than at the fringe, so if you don’t smoke’em when you center them, you don’t have an adequate fringe pattern. Has to be. Gotta be.
Shotgun Report’s Technoid
(Often in error, never in doubt.)