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Joined: 10 Aug 2009 Posts: 178 Location: New York

Hey 16 gaugers anyone have any experience with jug choking? I'm thinking about having Mike Orlen work on my cylinder/cylinder choked gun to get it up to maybe skeet/light mod. The gun isn't really a candidate for choke tubes and I hunt over pointing dogs. I've read good things about jug choking but don't have any direct experience with it.

I was measuring the chokes on a Arizaga 12 ga one day.bore.731, right muzzle .734. I'm thinking this thing is going to patten likea blunderbus.

To my surprise it threw a nice 27" at 20 yds, which would be IC. I measured about 3/4" back from the muzzle; it is .740. at 1/2 from the muzzle it comes back to .731 then flares out to .734. So it was jug choked and flared to the muzzle.

Member Joined: 31 Aug 2005 Posts: 1257 Location: Nebraska

Mike Orlen did a jug choke on my M21. The Modified barrel had been opened up leaving only .003" of choke and Mike's work added about .010" or .011" to get it to around .014". I have not patterned it extensively, but with limited checking using two different loadings found that barrel gave 15%+ tighter patterns than the gun's Cylinder barrel.

I'm happy with it.

Kirk

Back boring is another option w/ some guns. Opening the bore to just behind the choke section will make the barrel more efficient as well as tighten the choke. Some of both options can really help. Mike does a good job of backboring. I've had him do several barrels for me. I'd suggest discussing it with him.

Member Joined: 06 Oct 2007 Posts: 2350 Location: West MI

kgb, do you know what he did? Add an insert? Or swage/bead roll the barrel/muzzle down a bit? Can you see the difference form outside the barrel?

If it's not an insert and the choke is applied from the outside of the barrel it will be interesting to learn how or if it can applied to an O/U or SxS.

Member Joined: 01 Feb 2006 Posts: 450 Location: Indiana

I have a pigeon 101 and the top barrel is jug choked. Barrels are 30''. I throws a beautiful pattern at 35yrds on paper. On trap it just smashes them on shootoffs at 27yrd back to 35yrd.

Member Joined: 31 Aug 2005 Posts: 1257 Location: Nebraska

As 16gg said, it's done internally and from what I recall it's all piloted from the breech end of the barrels.

I haven't mapped out the whole choke, but can give a general idea. Bores of both barrels are .670", the left is a factory Cylinder and keeps that diameter through the muzzle of course.

The jug choked barrel starts opening at a point 4.3" back from the muzzle and reaches .682" at a point 2.3" from the muzzle. It is back to the bore diameter of .670" at a point 1" from the muzzle then constricts another .003" to .667" at the muzzle. Looks like a max of .015" now.

So, over 2" it expands to its max "overbore" and in the next 1.3" returns to the original bore diameter for a total "job" of 3.3" which is nearly all taper of some sort with no real parallel section. I don't know how the original choke was shaped or how the choke was originally opened but IIRC as I got the gun it was pretty much straight to around that 1"-from-the-muzzle point where it gained its .003" of constriction. To me, there is no practical difference between .000" and .005" or so of choke and I used that gun with the .000"/.003" combination for most of an entire season with satisfaction.

I suppose the Modified barrel had been opened because the chokes are the reverse of normal and some owner in the past didn't like the setup. I'm glad there was enough steel in the barrel to restore the choke, and you can't tell from the outside or glancing down the barrel.

Mike does fast, quality work.

Kirk

Member Joined: 06 Oct 2007 Posts: 2350 Location: West MI

Wow, very interesting, thanks for the detailed descriptions. I now understand the dimensions and profile of a jug choke. So, the muzzle doesn't really resrict more than it originally did, got it. And now the shot column is allowed to expand a bit out to the "jugged" dimension before being reorganized to the original choke/muzzle dimension the moment before leaving the barrel, got it.
Hmm.....
If the choke dimension at muzzle is the same diameter as it was; how does this have the net effect of tightening patterns? Does it lengthen the shot string by delaying/slowing the pellets traveling through the jug and "stretching" the shot column/cloud in turn reducing the clouds' cross sectional diameter; I.E. like stretching a wad of gum or dough?
My appologies to NY16ga if this appears as a thread highjacking. I'll start a new one if you'd like. My interst in this lies in 2 of my 11-48 barrels that have been cut back and the bore is too large to add tubes.

Joined: 06 Aug 2009 Posts: 960

putz463

A shot column traveling down a bore also has radial energy. i.e. it is pressing outward on the barrel walls as well as traveling down the bore. When the shot column reaches the 'jug' it expands outward because of the radial pressure. When the shot column reaches the muzzle which is back to the original bore size it is constricted again. It doesn't really matter that the jug portion is only a few inches long, the shot column isn't going to simply skip over it. It will expand to the jug size because of the radial pressure exerted on the shot column.

Maybe one of the engineering types can explain it better.

Very simple concept, probably doesn't work as well as a regular choke, but jug chokes do work better than you think and can get a guy out of a bad situation.

Joined: 10 Aug 2009 Posts: 178 Location: New York

Thanks for the detailed discussion everyone. I had a general idea how jug choking works but knowing the details and hearing from folks with some hands-on experience is always good. So it seems like everyone's saying that this is more or less a pretty good way to go if I'm trying to tighten up a cylinder choked gun, yes? I don't need extra full or anything like that. Mike said he could get it somewhere near SK/IC or maybe Light Mod which would be perfect since I'll mostly be hunting quail, grouse, and pheasants over my GWP.

Unless there's some risks I'm not aware of I think I'll give this a try and will probably have him lengthen the forcing cones too while he's at it. Hoping to get my little GWP pup out to the preserve in the next few months so I'll post results (the gun and the dog!)

The Tula choke was developed by the Russians for International Skeet back in the 1970s. They saw the patterns and results of the US shooters all of whom were using Cutts compensators on automatics and pumps. The Cutts was a sort of "super jug" choke - in that the shot column left the cylinder bore, jumped a 3 inch void inside a tube with an internal diameter if about 1 1/4 inches and then was choked by a screw-on barrel-sized tube with whatever choke was deemed appropriate by the shooter. Typically the skeet choke was about .004 smaller then the barrel ID. The Cutts was also ported. Use of the Cutta was the hot ticket up through the 1970s.
The story goes that the Russian coach was so impressed by the Cutts that he bought one of the guns from a US shooter when the competition was over. An hour later, he returned the gun to the shooter, less the last foot of the barrel and the Cutts - which he had sawed off. He was only interested in the dynamics of the Cutts.
Shortly thereafter the Russians showed up with their over-under Baikals with strange bulges at the end of the barrels - "Tula (for the Russian gunworks) chokes. Basically a jug choke with ports followed by a spreader portion. This choke type became very popular in International Skeet until it was found there was no advantage to using Tula chokes with the very light loads (24 grams - 7/8 ounce) mandated now.