More choke tube questions

[Oldnamvet]

Life seemed simpler when I didn't have choke tubes, just a full choke barrel single shot for everything. But progress...........
Question: Do choke tubes have specifications based upon percentage of shot into a certain area at a certain range OR are the specs simply on inside diameter?
I have noticed that the Remington skeet choke tube has an ID of .732 while Carlsons skeet tubes have an ID of .725 (12 gauge). This is quite a bit of difference. Huh?

 

[thinkat]

There is no way for a manufacturer to know how different loads will pattern out of your shotgun with their choke. So yes, the only number they generally give is the I.D. And to further complicate things for you, just because choke Brand A has more constriction, does not always mean a tighter pattern than Brand B. You have to experiment.

 

[Loyalist Dave]

Yep the man is correct, and my local smith says he judges choke by using calipers, and measuring the amount of constriction by percentage compared to the diameter of the rest of the barrel. So one maker is different from another.

PLUS..., if the choking was done way too soon, too far away from the muzzle, the shot column reacts as though coming out of a cylinder bore. So the choke has to constrict the shot column over a short distance..., but different makers do it different amounts both in diameter and distance. So our guns might have the same muzzle constriction, but if yours does it over a shorter distance, your choke might be tighter.

Next throw in the ammo. Lead reacts different than steel, and steel reacts different than bismuth, etc etc etc. I was taught that bismuth was made for barrels that didn't like steel, and that it acted more like lead. I have also been told that steel should be shot from a Mod barrel to act like the old lead Full. So...,my old 870 shouldn't shoot an old traditional full choke barrel with steel well, but for some reason my fixed choke 870 barrel loves steel. The point is you never know 'till you experiment.

I have a SxS that doesn't like #8 shot. Thows wierd patterns, in reloads or in factory shells, but loves #7.5 shot in about any configuration. Again, experiment.

LD

 

[RNB65]

Do choke tubes have specifications based upon percentage of shot into a certain area at a certain range OR are the specs simply on inside diameter?

Yes! The numbers (.7xx) are simply a measure of the muzzle diameter of the choke. What it means is purely subjective as there is no real standard when it comes to chokes.

The only way to know for sure what a choke is doing is to pattern it. Get big sheets of paper, mount them on a piece of plywood, and blast away. Then draw a 30" circle and start counting.

Believe it or not, patterning a shotgun can be fun. Really!

 

[sm]

Additional reading, and I am not affiliated with sites, just handy references is all.

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

http://www.trulockchokes.com/chokeinfo.asp


Personally - I'd just as soon have fixed chokes.