Jug chokes and round balls

[billd]

Will round balls still shoot accurately after a barrel is jug choked?

I did a search on this here and in the archives and found two results. One person says it will not change how round balls shoot and could actually make it more accurate and a different person said that it will make a barrel useless for round balls.

I want to build a 20 ga. smoothie and have it jugged choked for turkeys but if it won't shoot round balls afterwards it will be a waste of $800+ of my money.  As much as I'd like one, I don't have that kind of money to put out for a special purpose gun.

Any opinions??
Thanks,
Bill

[roundball]

I had a GM barrel Jug Choked 'full' for turkey's and was not satisfied how it shot PRBs after that compared to how it shot them before.

So I use it only for shot loads on turkey, squirrels, etc. and its outstanding for that...and even if I only used it for turkeys I'd still be pleased because it made all the difference in the world in terms of reach with pattern density for Flintlock turkey hunting using a bare bore, no modern shot cups, etc.

[George Sutton]

I have a 12 ga. with a jug choked barrel. It shoots round balls real well. It's a better round ball shooter than my 20 ga. Tulle.

With the 12 ga., accuracy holds up out to 100 yds. With the 20, it's real accurate out to 50 then drops off pretty quick. The 12 has a rear sight which may account for some of the difference.

Centershot

[arcticap]

I read a post about a TVM Colonial Fowler that was jugged choked full and afterward it shot into one hole at 25 yards, but that it opened up to 6 inches at 50.
How well a gun will shoot could depend on how much jug choke is added and who performs the work.
Someone else mentioned that he test fired a bare ball at 50 yards and it was surprisingly accurate. Go figure! 
I think that a person would be better off having a 2nd barrel jug choked and dedicated to shot loads. 
 

[Daryl]

I agree with Arcticap - the degree of choke might effect how well the gun shoots 'after'.  My .44 only had about .006" of choke- and shot round balls exceptionally well.  .006" is an Improved Cylinder choke in a normal modern shotgun.  Full choke is 40 points of choke- ie: .040". That is deep (tight) whatever you want to call it.  When the patched ball enters this 'wide' area, the powder gasses can bypass the ball and burn up the patch - note I said Can.  If this happens, you might as well be shooting a bare ball with card wads. Some guns even shoot well with that.

 As to accuracy, it is normal for a 20 bore to shoot 1 hole at 25 yards and open to 6" at 50. It needs load development. The last 20 I tested made several 3", 5 shot groups at 50 yards off the bags, along with 1" holes for 5 shots at 25 yards.  There are 1 hole groups, and there are 1 hole groups. One can be over twice as large as the other yet both described as 1 hole groups.  We used a .595" ball and .025" denim patch with LHV lube. THAT is a tight load, measuring .645" side to side, in a .620" bore or maybe .615" bore.  We also used 85gr. 2F which isn't a heavy load but you know when it goes off in a 7 1/2 pound gun that has a too-high comb.

[Dan]

I'm puzzled by one aspect of this discussion. Recalling that chokes were not always used on many old fowling pieces I'm left to wonder why one would necessarily want to choke a gun that already shoots RBs well...if I understand what y'all are talking about.  Cylinder bores can shoot good groups with thoughtful loading, so............

[Daryl]

Cylinder bore shooters usually have a bit of work in front of them to find a load that doesn't shoot donut patterns.  If you've got a load that shoots well, GREATl  Some shooters want to use their gun for turkey or migratory birds and for RB hunting too, big game one the menue.

  In order to extend their shotgunning range, jug choking is a natural for a bore that doesn't have enough barrel wall for back-boring - the preferred system for choking today.  For instance, if you wanted a full normal choke in a gun barrel, you'd start with a 14 guage tube and leave about 1" to 1 1/4" of the end of the barrel, the nominal .690" (full choked 12 bore), then back-bore it to 12 bore. That way, it would have a standard full choke. The end-choke, the last 1" to 1 1/4" 'normallizes the shot charge before it exits the bore. This type of choke usually delivers better patterns than a swaged choke, where the end of the barrel is hammered or swaged down to the choke 'size' desired.  For the full choked 20 bore barrel, a tube of .575" would be used, and back-bored to .615" - again, leaving .040" of choke.
  On a gun barrel already made, reaming or ginding out a 3" long section of the bore, 1" back form the muzzle is easier and doesn't change the size of the barrel's  bore yet gives a choking or tightening effect to the shot cloud, effectively closing in the do-nuts of the cylinder shot cloud and extending the shot cloud's killng range.  Jug chokes usually weren't ground out deeply, until just recently. The normal jug choke was only up to about .010" judging from what I've read on the subject, about 1/2 way between an improved cylinder and modified choke. Today, they are being round much more deeply by some businesses, witness what they are calling a full jug choke. I doubt it has .040" thou per side depth - but you never know for sure until you measure one. I haven't. .040" is a lot of choke and perhaps that one won't shoot round ball well.

 Had to edit this - I was fallng asleep as I worte the initial post.

[northmn]

A few points to nitpick on Daryl's comments.  Full chokes today are rarely .04 which is now an Extra Full.   Today they restrict to .035 and call it a full choke.  Also we are talking about 12 gauge only.  The restrictions required for choking decrease as the bore size decreases.  A 20 bore full choke is listed at .025 for a restriction.  It took me a bit to find the tables on this as I rememered that point.  A 410 for instance only has a .017 restriction to have a full choke.  For instance his .006 in a 44 cal would be farily close to a modified.  His comments about cylinder bore is essentially correct and the skeet choke was developed at about .005 in a 12 to eliminate that problem.  However the Russians came along with a Tulle choke which was actually larger or an expansion of bore diameter.  The issue of getting a tight pattern and good RB/Slug shooting has eluded shooters even today.  In the good old days of Foster slugs modified was considered about the tightest for accuracy.  Thats why modern shotguns like Mossberg push off these two barrel packages.  While I do not know if the constrictions hold the same for jug chokes, I expect that they do.  Also remember that there is a full choke pattern, which is shot performance, and a full choke constriction which is the most likely to deliver those patterns.  They are often not the same.   Patterning is the only true determination.  The turkey choke is so specialized that either two barrels or two guns is the best answer.  For most shotgunning, especially with a flintlock fowler,  if you want to do a little wing shooting, full choke is too much.

DP

[Daryl]

 Spot-on DP - .040" was the standard for 12 and 10 bores when multi-wads columns were being used.  Plastic wads shot tighter than the old standards and I presume choking was redcued due to that.   I'm a little 'behind' the times, I guess.  With modern 12 bores being as large as .735" to .740", it's difficult to talk about norms & know what chokes are today.

 

[billd]

Thanks for the answers.  To make sure I'm understandinging what everyone is saying.......If I get the barrel jug choked, it may or may not shot RB. The less choke I get put in it, the greater the chance it will shoot RB.....  Did I get this right? 

I want the gun for turkeys.  How much choke would you recommend and who does the best job?

Thanks,
Bill

[roundball]

This is who I used for two GM barrels...one Full, the other chocked Imp.Cyl.+
$75 (3 years ago)

Lowell Tennyson
209 E Lotte St.
Blue Grass IA. 52726
563-381-3711
Kb0ba@att.net

The 'FULL' Jug Choke in combination with the load info from Bob Spencer's website
http://members.aye.net/~bspen/SmoothboreLoads.html
drops turkeys in their tracks stone dead with head shots at 40yds...use whatever load you're comfortable with of course.

Lowell will need to know what barrel you have and how much barrel wall thickness there is in the last 4" of the muzzle end.

[Daryl]

Bill, I'd not go with more choke than an Imp Cyl.  It will shoot nice patterns and should work well to 30 yards easy with a bit of load development on shot and should still shoot round balls just fine.

[roundball]

I have no interest in challenging anything here Daryl, just worried that an I.C. choke might be too thin "to count on consistently"...when I got into this Jug Choking stuff I made a pretty fair number of trips to the range and went through a lot of pattern testing with each of my Jug Choked barrels...different powder charges, wad configurations, shot sizes, lead, magnum lead, copper plated, and nickel plated shot....then different distances including penetration tests on heavy metal cans, etc.

Based on those experiences...as hard as it is to get a tom in the sights of a Flintlock, I personally wouldn't go turkey hunting and bet $5 that an Improved Cylinder choke will consistently put enough pellets into the "kill zones" of a turkey head at 30yds to kill it every time...key word of course is consistently...might roll a tom at 30yds sometimes, but then again there will be times when he'll run/fly away.

Pellet count can be bumped up to better saturate a paper target to look better with more holes by using 7.5's but then actual penetration and bone breaking capability is compromised with the lighter pellets.  The kill zone in a turkey head is even much smaller than the head itself...we're talking about a brain the size of a walnut at best, and a neck vertebrae no larger than the diameter of a common wooden pencil...very tiny areas to consistently hit with a few pellets each time at 30 yards...and pellets that go through the rest of the jelly fat & loose skin don't do a thing of course.

With my full jug choke, I'll shoot a tom at 40yds without hesitation...but I will not shoot at one at 50yds because even with a full choke the pattern is too thin and I don't want to wound/lose a turkey...my worry about an IC choke is that same condition would prevail at 30yds.  In the end, anybody can use whatever they want of course, just wanted to toss out some additional findings and thoughts accumulated while I was playing around with a jug choke barrel for turkeys.

[billd]

Daryl and Roundball,    You both make sense. I'm talking about a 20 ga.  What are your refering to?

Thanks,
Bill

[roundball]

Mine are both GM .62cal/.20ga Flint smoothbore barrels, 1" x 33"

[Dan]

Sorta thought that was what you were speaking to Daryl, thanks. 

On the point of blown patterns I would offer this, only in context of the effect of choke and patterns.  I do not know if the cause if understood, maybe yes and maybe no, but I don't think open bores are directly responsible for blown patterns.  If they were, it would be common in IC chokes, or more so in Skeet 1.  It isn't.  Load work up has great influence on the pattern and perhaps more often than not the use of lower or reduced powder charges exhibits a much tighter pattern than a given choke would indicate.  This phenomena is common with modern shotguns on the skeet range where reduced loads are common place.  An example I'm personally familiar with is a Skeet 1 choke with 7/8th ounce loads in a 12 bore. 

Now I recognize we aren't talking the use of shot cups here but in reference to the older guns, but I'm aware of a number of fellows shooting old BP shotguns, both cartridge and muzzle loader varieties which provide very good patterns and are effective on waterfowl....with cylinder bores. It does reduce effective range somewhat but does not necessarily result in blown patterns.  My guess is that lower pressures and velocity has a great deal to do with that.  Back in the day of BP chokes were not that common and loads were milder for a given gauge, both in terms of powder and shot.  They killed a lot of birds like that, probably even some turkeys too.

Anyway, I'd sure explore less powder and/or wad variations before installing a choke in a smoothbore. I'd also suggest that you can let a turkey get closer than 30 yards before shooting.  I know hogs are not as crafty as turkeys but sometimes I'm inside of 10' when I shoot them....and it's been a long while since I shot one beyond 15 yards.  I've shot turkeys that close too.

[northmn]

The reason the skeet choke was invented is that blown patterns are caused by the wads hitting the back of the shot column.  The choke slows the wads and permits the shot to outrun the wads.  A good explanation of chokes is explained by Don Zutz in his book Shotgun Stuff. Even in modern guns, cylinder bores are said to tend to donut.  When the credited originator of the choke system worked on chokes he overchoked and got patterns worse than cylinder.  He thought he removed the choke and tried again and got an exceptional pattern.  Remeasured and realized how little it took.  The "backboring" of modern 12's has not changed the constriction rates, just the pattern characteristics, a full is still .035 constriction.  Stan Baker started "backboring" for trap and the use of magnum loads.  Some used 10 bore barrels in 12 gauges.  Essentially no forcing cones.  Backboring tends to throw strong center density in patterns which makes it great for trap guns.  Its development came with plastic wads which could expand to seal the bore.  In a ML there is no such thing.  A bore is a bore.   I have shot a lot of ducks with a open bored ML when it was legal to use lead and had adequate patterns, but over decoys.  There are tricks to tighten patterns, such as roughening the end of the barrel, an old market hunter trick, plastic wads, and special shot like Tungsten, but you still will have trouble making a full choke.  Life is easier when you use the tool designed for the job.

DP

[Steve-In]

Bill I have turkey hunted a little and messed with patterns both ML & breech.  I would build this gun with a full choke.  I would build it with a hook breech with adding a second barrel if needed in mind.  Test the tight choked barrel with PRB to see if you can get acceptable groups.  If you can't add the other barrel for round ball.

[Daryl]

As to range of shooting turkeys, I'd assume that has to do with experience and cover - both are extremely important with a smart and fidgety critter.  Guys from all parts of the States whom I've met on hunts up here for moose, hunt turkey every year in their own locals - but use only long bows or recurves. They shoot from blinds and will not shoot beyond 20 yards.  They are good shots.

DP's got the scoop on boring today, and yesterday as well.  My own shot testing from cylinders in ML guns and ctg. goes back to the 70's, as I'm sure RB's does.  Taylor's Manton has 15 bore tubes and we were able to find a load that ran consistant 72% patterns at 26 yards with tight centre concentration. That would be the max range I'd use it on turkey's.  With slight improvement, ie: IC choking, I am positive that another 4 yards, ie: 30 yards would be OK on turkeys - maybe even more - load development is part and parcel with shotgun loading as it is with round ball loading in a smoothbore or rifle.  This was the basis for my 30 yard prediction.  I don't think a cylinder or jugged 20 bore makes the 'best' or even a good turkey shotgun. The bore, to me, is too small. I'd prefer a 16 or larger. I don't believe in loading a 20 bore as if it was a 10 or 8 bore.  I think 1 oz should do the goods. If not, then a larger bore is needed.  We were shooting 1 1/8oz of shot in Taylor's 15 bore and obtained excellent patterns with it for standing shots. I'd think 1oz might do even better on moving targets due to a shorter shot string.  It is a decoy-distance shooting gun, no more.  For a 20 bore, I'd start at 7/8oz. and perhaps go to 1oz. for a heavy load - with normal shot and wad columns.  Shot protectors can help with patterns from cylinders.  They can be plastic or paper - one had to experiment.  what works in one gun does not necessarily work in another.

[FL-Flintlock]

Resultant patterns from a Tula/Jug choke are controlled more by the transitional and running angles and/or radii in addition to the length of the distended area(s) proportional to the nominal bore diameter, individual pellet mass & diameter, velocity and total effective payload length as opposed to simply by the amount of distension.  I put a Tula choke into my 20" CF 12ga cylinder bore barrel, no ill affects on accuracy with Foster style slugs, #4 & OOB patterns were reduced by about 20% ... but most impressive was the effective pattern density increase at 40yds with 1oz of #5 shot that went from best possible pattern being only 18% with the OEM bore and a "tuned" load to 50% with the same load after adding Tula choke, then to 67% after re-working the load for the choked bore.  The maximum bore diameter increase is only 0.017"   Every barrel is a little different and will require load tuning but the manner of making the choke can have a dramatic affect on the resultant patterns.  In a cylinder bore 24ga 28" long flintlock bbl I obtained the best pattern using 3/4oz of shot and 55gr 2F, 0.125" nitro card & 0.5" fiber cushion split into three pieces.  After cutting a basic parallel jug 0.008" the pattern density with the same load increased about 20% - same barrel re-cut with a Tula choke style where the maximum diameter increase was to 0.010" but the shape and length of the distended area was changed, the same load showed almost 45% density increase over the cylinder bore.  Staying with the same wad column and shot charge, the powder was changed to 60gr of 3F to produce the best pattern density. 

Static patterns do not give an adequate representation of load performance for wing shooting because the larger the payload the longer the shot string which can vary from 8' to more than 20' depending on the bore diameter and payload volume.  The velocity of running or flying critters can vary from 12 to 100 feet per second thus the longer the shot string the lower the effective pellet count becomes at any given point within the string.  The string is also spread at an angle to the plane of the bore relative to the speed and direction at which the bore is being moved.

The biggest problem with patterns in all bore sizes, no matter if modern or traditional is normally caused by overloading.  As stated above, the shot string length is critical to performance because that is what determines the pellet concentration at any given point in time on a moving target be it a goose or micro-clay.  Look at this way, if you're running a 1.5oz load of #4 shot and you recover a goose that's got 11 hits with 7 of them being solid fatal hits, your pattern effectiveness on that shot is only 3.5% - looking at a different way is that 191 of the 202 pellets missed the target.   If you reduce the payload to 1 ounce shortening the shot string and recover the next goose now with 22 hits, you have doubled "effective" pellet concentration.  Yes, this will make scoring hits on clays a little more difficult but when it comes to taking game it means greatly reducing the chances of sending a critter off to be wasted with just a few delayed mortality wounds.  With proper load development, the "effective pellet concentration" of a 20ga can easily match that produced by a 10ga and given that the velocity remains the same for a proportional load of the same pellets no matter what the bore diameter, there is no difference in the wound channel creation and penetration ability of the individual pellets. 

I don't recall who said it but the one quote that keeps coming to mind about back-boring is the fellow who claimed, "It's like throwing up a wall of shot."  Subsequent evaluation of the particular load (Winchester 12ga AA 1.125oz 7.5 shot) and the parameters of the gun, the whole thing boiled down to the fact that the back-bore increased the bore volume lowering the pressure & velocity of the load causing the wad to push into the pattern enough to spread it out in an oval shape - worked perfectly for the skeet shooting application but was absolutely useless for any type of hunting because the effective shot concentration was reduced far below acceptable levels.  The exact same pattern results were duplicated by simply reducing the powder charge to produce the lower pressure & lower velocity created by the back-boring.   

If one chooses to do so, more time and effort can be put into just one shotgun load & bore tuning exercise than building loads for a dozen rifles.

Using bore-size RB's or RB's increased to bore-size with paper patch and loaded between wads rather than with a cloth patch will usually quell group dispersion issues if load tuning fails to achieve the desired results. 

[billd]

What is a tula choke?

[roundball]

A Jug Choke...

[Daryl]

As Roger mentioned, the Tula has particular shape to the entrance and exit of the jug choke.  Also, I think the depth of the 'jug' changes within it's legnth, but that might be in error. I'm trying to remember from a 1970's Gun Digest article on them.  I do know (I think) that the Russians soundly won an International Skeet Shooting Championship with them.
 The jog choke I honed and lapped into my .44 bore had a 1" long entrance and 1" long exit, as even as I could make them and was 3" long before the tapers, making it 5" in length altogether. It was only .007" deep, but really evened and closed up the pattern.   

[FL-Flintlock]

As Roger mentioned, the Tula has particular shape to the entrance and exit of the jug choke.  Also, I think the depth of the 'jug' changes within it's legnth, but that might be in error. I'm trying to remember from a 1970's Gun Digest article on them.  I do know (I think) that the Russians soundly won an International Skeet Shooting Championship with them.
 The jog choke I honed and lapped into my .44 bore had a 1" long entrance and 1" long exit, as even as I could make them and was 3" long before the tapers, making it 5" in length altogether. It was only .007" deep, but really evened and closed up the pattern.   

Daryl,

You're not in error at all.  IIRC, the "Olympic" Tula choke had two distended areas of differing lengths and shapes with the muzzle diameter actually being slightly larger than the nominal bore diameter.  That choke was specifically designed to produce fairly even pellet distribution throughout a rather long & wide oval shape.  An interesting side note is that all of their shooters practiced using chokes that produced an extremely compact pattern and short shot string in order to get them into being dead-on, changing to the Olympic choked guns for the actual competition, it compensated for shooter error.

The shape, length and diameter does control the pattern density and length of the shot string.  Function of the basic Tula choke is much like the basic parallel Jug choke however a properly shaped Tula will allow for finer tuning of the pattern density via the load parameters.  When you get into the more advanced styles of Tula chokes, such as those used by the Olympic team, they can become very load-specific in that it may only shoot one or two loads extremely well and not be worth a hoot for anything else.

[northmn]

The British game guns are only guaranteed for one load as to pattern.  While they may work OK with others, that's their way of avoiding hassle.  Another variation of the TULA choke was the old Lyman Cutts Compensator.  Skeet shooters are claimed to like extended shot strings as the oval shape assists in making hits if you learn to slightly overlead.  Some also like soft shot for this reason.  Backboring was a trap shooter thing and some modern guns have picked up on it as it seems to have higher center densities than standard bore.  As stated turkey loads were developed to be lower pressure lower velocity loads that do the same thing.  Shot string for a stationary target such as a turkey does not mean much.  Tom Roster used to preach what Flinter was saying and found that really, in a 12 ga 3" you gain almost nothing using more than 1 1/2 ounce of shot as to pattern density.  I tried some once and I cannot disagree.  V.M. Starr used to preach about the use of two hard card wads in BP loads.  Yet in modern loads the 3" will pattern better with heavy loads as it cushions the shot better.  A 1 1/8 ounce load in a 20 ga 3" will perform and pattern very well, the short baby mag makes an improved cylinder out of a full choke.  Since ML's have no case restrictions one should be able to use a little heavier charges well, however, I feel the 1 1/8 is about the limit for a 20 and probably Roster's claim of 1 1/2 for a 12 to be reasonable.  In the BP days loads were generally listed as more conservative with 1 1/8 in a 12 to be common.

DP