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putz463
PostPosted: Mon Jan 27, 2020 3:20 am  Reply with quote
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In another thread it was suggested that adding a Jug Choke will help add choking to a somewhat open choked gun. Certainly a helpful suggestion to try and solve a tightening effect to the gun. But, I'd love to find someone who can share exactly how a jug choke works. Not trying to be argumentative, it has been proven to work and I will not argue with proof in the pudding. I simply want to understand the dynamics of how allowing a column of pellets to expand slightly and then compressing them back to the same dimension prior to jugging has any net choking effect.

Anyone know this?

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MSM2019
PostPosted: Mon Jan 27, 2020 5:35 am  Reply with quote



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The shot column does not 'see' the trip down the barrel. It only 'sees' the larger bore at the jug and the taper back down to a smaller bore diameter which is how all chokes work.

I don't have a gun with a jug choke, but I would guess that things probably aren't quite as predictable and uniform as a good bore/choke setup normally is.

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putz463
PostPosted: Mon Jan 27, 2020 7:57 am  Reply with quote
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MSM2019 wrote:
The shot column does not 'see' the trip down the barrel. It only 'sees' the larger bore at the jug and the taper back down to a smaller bore diameter which is how all chokes work.


Completely understood, what I can't picture or understand is if the original muzzle or choke dimension stays the same; how does the brief expansion of the shot column' diameter effect the shot any more than when it wasn't allowed to expand? I.e.; going from a 0.665" Cyl bore to say (un-jugged) a 0.662" Skt choke compared to going from a 0.665" Cyl bore to say (jugged) 0.670" then back down to 0.662" Skt... how is the exiting shot any different? Or for that matter tightened??

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Riflemeister
PostPosted: Mon Jan 27, 2020 8:34 am  Reply with quote
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I had a Mossberg 935 3 1/2" magnum shotgun I got for goose and turkey hunting. The 935 was a 12 ga with a 10 gauge bore. I wasn't sure how that would work, but although the choke tubes were a bit oversize for a 12 ga, they all shot the pattern as marked and the patterns were quite good. With a Kick's turkey choke installed and a red dot sight I took it to a fundraising turkey shoot and won three turkeys (which I donated back) before I just stopped entering. Just imagine the Jug choke as a shorter section of that 935 barrel. My nephew wanted to sell his 16 ga SXS to buy a 3 1/2" magnum goose gun, so I told him to keep the 16 ga and I'd give him my Mossberg. Now he's just absolute death on turkeys and geese.

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fn16ga
PostPosted: Mon Jan 27, 2020 12:22 pm  Reply with quote
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Its the constriction of the shot column . Using your dimensions ., .670 to .662 would be . 008 of choke = I/C .

Lets say you had a barrel that was bored .670 all the way down the barrel then hit the .662 (.008) of choke at the end .No different than any other choked barrel.


Last edited by fn16ga on Mon Jan 27, 2020 6:09 pm; edited 1 time in total
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John Singer
PostPosted: Mon Jan 27, 2020 12:58 pm  Reply with quote



Joined: 03 Sep 2014
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Location: Rochester, MN

One of my favorite books that I own is The Shotgun Book by Jack O'Conner. It was published in 1972.

On page 97, Jack references a recess or jug choke as follows:

"Another type of choke is the recess choke. As far as I know, no factory uses it, but it is a makeshift used to put some choke back in barrels that have had all of the choke cut off. For this type of choke a recess is cut in the barrel starting about one-half inch back of the muzzle and extending 1 1/2 to 2 inches back toward the breech. This enables the shot column to expand a bit and then compress, and if the job is skillfully done, a straight cylinder barrel patterning from 35 to 40 percent can be turned into an improved cylinder or modified barrel patterning from 45 to as much as 55 percent."

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4setters
PostPosted: Mon Jan 27, 2020 4:09 pm  Reply with quote
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For what it is worth, I owned a 12 gauge Model 12 trap gun for many years that was jug choked, or so I was told by the gentleman that shot trap with it from the 50s through the mid 80s. According to him, jug chokes (sometimes called Russian Choke I believe) were all the rage among trap shooters at some point in time during this span, so he had his gun bored cylinder (taking the factory full choke out) and jugged. Since I never performed any measurements on the barrel, I can't vouch for what he said.

The gun sure shot like a dream. I very rarely shot trap with it, but the few times I did, I shot like 24 out of 25.

The gentleman who sold it to me had to stop trap shooting due to a heart condition. It was "worn out" from all the use; I had Nu-Line rebuild it just because I felt like it deserved to be restored. At a great loss, I sold it to the father of a 15 year old high school shooting program participant a couple of years ago. Perhaps it is living up to a Model 12 legacy now.

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kgb
PostPosted: Mon Jan 27, 2020 6:29 pm  Reply with quote
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I've got 2 jug-choked 16ga barrels, both done by Mike Orlen. The first took the constriction from .003" to about .012" from the bore measurement. Pulling a gauge through the barrel I found the opening behind the choke to be pretty short. Well shorter than the length of a wad's shotcup. Doesn't matter, as with the same shell I found it shot 15 percent tighter than a straight cylinder choke. This was at less than 40 yards, but it was in line with what I was wanting.

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putz463
PostPosted: Tue Jan 28, 2020 1:18 am  Reply with quote
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Thanks for the patient responses, I guess I'm looking only at the exit diameter and not considering the larger bore diameter directly behind the constriction and how it effects the flow of pellets through the choke. My stubborn mind, in simple terms, sees a garden hose nozzle on the end of a piece of 1/2" pipe then again a 1" pipe and the stream of water not changing due to the same exit/nozzle constriction all else equal.

Something more to think about waiting for birds during late Goose split.

Thanks John, I'll try and find a copy of O'Conner' The Shotgun Book.

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Cold Iron
PostPosted: Tue Jan 28, 2020 10:50 am  Reply with quote



Joined: 09 Mar 2016
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I picked up a CZ 16 ga. Sharptail last Spring which was supposed to be choked IC\Mod. Last Wednesday shot with Dave Erickson and he was kind enough to bring his Skeets Bore Gauge and measure the bbl. for me. .001 and .011 I spent the weekend going down the jugchoke rabbit hole LOL. Not sure I want to spend the money for Briley to install thinwalls so was looking at options. Still not sure. Yet.

Jug choke\Cutts Compensator\Tula chokes all supposedly work roughly the same. But there is some disagreement on HOW they work. Some say shot can not be treated like a fluid and fluid dynamics. Others say it can. Some say those chokes help push the outer pellets back in the shot string to shoot tighter. And some say they were made for felt wads and don't work with plastic wads. Others say they do.

The most interesting thing I found was testing done by Neil Winston. A cylinder choke installed in a gun shoots roughly the same as a fixed .005 choked gun. And therefore tighter than a true cylinder bore, even though it is a cylinder choke. Just the little bit of opening at the base of a choke tube skirt to prevent a wad from catching is enough to tighten the pattern. Apparently it does not take much to work, and it does work with plastic wads.

How it works seems to be open to debate.
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WyoChukar
PostPosted: Tue Jan 28, 2020 10:23 pm  Reply with quote



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I have jug choked two of my own guns; still own the 28 ga. It does work. Basically, the shot charge/ wad combo expands into the larger diameter overbore section then squeezes through what is now a greater degree of choke.

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Flintsteel
PostPosted: Wed Jan 29, 2020 8:39 pm  Reply with quote



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I have a 1870 12 ga Scott that has jug chokes in both barrels. It was originally made as cylinder. Regularly shoot sporting clays with it and can say there is seldom a presentation I’m not confident the gun is up to. Parallel in the jug is probably 1 1/2”. I say go for it, you’ll not hurt the gun.

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putz463
PostPosted: Mon Feb 03, 2020 6:09 am  Reply with quote
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Good stuff, I find this subject very interesting, and maybe considered by some as KGB's sig line suggests...Bore, n. Shotgun enthusiast's synonym for "gauge" ; everybody else's synonym for "shotgun enthusiast." - Ed Zern Very Happy

Found this very interesting description of the choke and after reading much about how it helps smoothbore muzzle loading it seems to help stacked/un-shot cupped loads more but still helping "modern" ammo to a degree...

https://shotgunreport.com/2014/03/21/tula-chokes/

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Ohio Wirehair
PostPosted: Mon Feb 03, 2020 7:52 pm  Reply with quote



Joined: 24 Jul 2016
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I too jug choked a Ithaca 37 I bought with a damaged muzzle I removed. Although time consuming it worked well.
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putz463
PostPosted: Thu Feb 06, 2020 3:04 am  Reply with quote
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John Singer wrote:
One of my favorite books that I own is The Shotgun Book by Jack O'Conner. It was published in 1972.


Thanks John, found a copy on Ebay, informative enjoyable read. In it is a reference to another book, The Mysteries Of Shotgun Patterns, Oberfell & Thompson, that I will be looking for a copy of as well.

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