doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Choke Constriction Charts - Comparing

Hi all, was doing a bit of thinking (I know bad idea!) anyway, there seems to be a bit of differences in a couple of the charts I've used in the past (granted not by much, but still some differences).

Which of these charts is the most accurate in your opinion?

http://www.colonialarms.com/chokespecs.html

or

http://www.hallowellco.com/choke_chart.htm

If there are other charts, that are "better" I'd like to have a link to them.

Thanks so much!!

Greg

Of the two you cite, I like the Colonial Arms Chart because it's more specific and certainly easier to read, others may like Briley's Choke Chart. As far as accuracy of the charts is concerned, it's probably more dependent on the gun and the load than what is stated in the charts.
http://www.briley.com/2009/chokeconstrictions.html

Hi, I totally agree with you on the gun and load. Each is different. But one does have to have a baseline or rule of thumb to start with.

Thanks so much for your input! It's appreciated.

All the best!

Greg

With the exception of the "LTSK" and "IMK" columns, the Briley chart is the one that I see when I close my eyes.

The water is even muddier than those charts illustrate. If you do a search for the nominal definitions of choke (% at 40 yds) you will see what I mean. Is IC 45%? 50%? Depends on who you read.

Then, consider that shotcups skewed just about every vintage shotgun barrel in the tighter direction. Full = just 70%? Guess again.

Then there are the skeet definitions which, originally (sorry, Briley), weren't defined as a % at 40 yds at all.

I've pretty much stopped even thinking in terms of anything but numerical points of constriction. What's in my ASE90? .019 and .019.

Sam

choke article

If you are thinking about choke selection, I came across this article on another forum and it is one of the better ones I have read on the subject.

My pattern testing of pattern performance, i.e. choke, has been in line with the Briley table. That was of course conducted with modern plastic shot cups and hardened shot.

The three tables are not far apart and with a change in components or even guns, all could certainly produce the pattern densities as listed.

Please remember that barrel constrictions as commonly referred to as "chokes", are not only the overall constriction but also the angle of compression. The shot column flows through the constriction and accelerates when squeezed as water does through a nozzle on a garden hose. Smaller shot would seem to flow through a smaller hole than the bore easier than would larger shot. That difference may affect a pattern.

The barrel constrictions of classic shotguns such as Parkers and LC Smiths were usually 3" or more in total length. Modern "chokes" have an inch or so of total constriction to achieve the same effect. Yes, today we have plastic shot cups and hardened shot that allow sharper angles of constriction to work properly. My point is that given constriction may not be the same from gun to gun.

Hi Greg,

I think Eightbore sent me this one back in 2006:



Best regards,

JC

I have found if you have a tight choke relieved you end up with a much longer parallel than normal for a more open choke.
In one particular gun this still gave me around half choke patterns in spite of the 10 thou constriction.
However it only took another few thou to give me Improved cylinder patterns.
Another gun I tested recently has 14 thou constriction but gives nice IC patterns.
This particular gun has been taken out to .739 in the bore and has rather a long cone into the choke.
I too have given up on trying to guess with old guns based on constriction ,patterning is vital.
Although as you say it does give you some sort of baseline.
If I'm short on time I have found patterns measured at 10 yards are pretty indicative of 40 yard results.

When I think of choke, I think in terms of constriction in thousandths of an inch. The "full, modified, etc., nomenclature carries a lot of baggage with it. I don't bore my chokes out to suit a load, nor do I chose a load to meet the percentage pattern published for constriction. It's all just a guide and an expectation that full choke will be tighter with a given load than modified, IC, etc.. Better time spent doing something more productive like shooting or having a beer.