Shotgun Screw in Chokes Question.

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recoil 5

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I have a Remington 870 with factory screw in chokes and a Browning Citori with factory screw in chokes .
The choke diameter is quite different, when I compare the two. For example the Mod in the Rem, diameter measures .710
The Browning Mod,measures .720. The Rem full,diameter, measures .695, and the Citori full
measures at .705.
The I.C. on the Rem has a choke diameter of.720, the Browning .730.

Question is why? Shouldn’t they both be the same?
 
No, it isn't about the exit hole size. It's about how much the choke contricts compared to barrel full cylinder bore. The browning is likely backbored to a larger diameter than the remington. The contriction would be essentially the same.
 
The citori has a larger inside diameter than the Remington.

The diameter that a choke tube needs to be is directly related to what diameter the inside of the barrel is. A larger diameter barrel needs a larger diameter choke to give the same constriction.
 
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A handy tool.
 
Mentioned my situation to a so called dealer and , ....again , no convincing answer.
Nobody seems to have a simple answer to my question.
Why does one choke tube measure differently from a similar choke situation.in my case it is Remington vs Browning choke tube diameter differences.
 
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You got three correct answers now in post 3, 4 and 7.

Choke size is determined by constiction relative to the bore diameter. A full choke on an overbored barrel will be larger then a full choke on a nominal bore barrel. Both chokes are still full chokes regardless of the size difference between both chokes.

The dealer you spoke to is in the wrong business if he/she doesnt know this
 
FLHTCUI said:
https://www.chuckhawks.com/shotgun_mysteries.htm
Click to expand...

Your post addresses nothing with regards to choke sizes. All it addresses is the fact that some consider overbored barrels useless. Regardless of what ones position is on the matter of bore diameter...it doesnt change what a choke is or what it does. And that choke size is determined by the constriction relative to bore diameter....what ever that bore diameter happens to be.

The OP’s original post was a question about why two modified chokes from different manufacturers are different. He wasnt asking about benefits (or lack of) of overbored barrels. He was very specific in asking “shouldnt they be the same”? And he was provided the correct response three times
 
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Basically, a choke tube is matched to the bore of the shotgun and then the difference between the maximum bore diameter and the minimum choke diameter is the constriction. The constriction is the measurement that you see on the choke.

The reason that your tubes are marked the same, but measure differently is because the bore diameter of the two barrels that they go in are different. 12 gauge shotguns can have different bore diameters, which will range from approximately .725 to .800. So a modified (.020) choke for a .725 barrel will measure .705 and a modifed choke for an .800 barrel will measure .780.

Here is a link for you ...

https://www.briley.com/c-456-understanding-chokes.aspx
 
Yes choke diameter for a given choke designation relies on the bore diameter as repeated numerous times in this thread. One thing to note also is that different manufacturers have also had different definition of percentage of pellets inside a given diameter circle at a set distance. Winchester and Browning have had different parameters for degree of choke. Browning in the past days of fixed chokes had more dense patterns for named degree of choke than Winchester. ie a modified Winchester choke would throw a more open pattern than a modified Browning choke. It can also be that way with the multitude of choke tube manufacturers as well. Just look at their published degree of choke for named choke. They often vary between manufacturer. Unless you actually pattern test the load you shoot the name on the choke is only a guideline. I won't get into shape of choke and its effect be it conical, taper to parallel, swagged etc etc.
 
The correct answer has been posted several times with the OP not really understanding these answers. Try this...... the inside barrel diameter is considerably different for Browning barrels and Remington barrels, Browning bores are considerably larger, so their choke diameters are also considerably larger. Example, perhaps a Remington bore is .734"and a sample full choke constriction is .034". The degree of choke is the difference between the bore size and the choke size. Subtract .034" from .734"and that full choke should actually measure .700". Now compare a typically overbored Browning with a bore of .750" and a typical full choke constriction of .034". Subtract .034" from that big .750" bore and that Browning choke will measure .716" internally. Both of those chokes are full choke and both will produce similar patterns but these choke tubes will of course not be interchangeable between the two guns. If you can't follow the math blame your grade two teacher.
 
Melvin said:
One thing to note also is that different manufacturers have also had different definition of percentage of pellets inside a given diameter circle at a set distance. Winchester and Browning have had different parameters for degree of choke. Browning in the past days of fixed chokes had more dense patterns for named degree of choke than Winchester. ie a modified Winchester choke would throw a more open pattern than a modified Browning choke. It can also be that way with the multitude of choke tube manufacturers as well.
Click to expand...


Makes complete sense to me, I have a 14” 870 barrel that is externally threaded for a choke adapter that takes Win chokes. When I patterned it I get similar spread with the full Win choke as I do with my Mod Rem chokes.
 
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