Jug Choking ?

[Velocette]

I now have a second set of these fierce looking Brno 301 barrels also choked cylinder and cylinder. Whist I do use  the original cylinder/cylinder pair, to some effect on the right occasion I would like to have a tad more choke, 0.005" in at least one barrel of the new set and wondered if this can be achieved by jug choking. The barrel walls at the muzzle have plenty of meat on them so they should be safe to open out a little. Has anyone had this done, by whom, and were they happy with the result ?

[wymberley]

Is that the same as what we know as recess chokes?

[Velocette]

I believe it is.

[dipper]

Jug choke I had a Greener blue rock one of the barrels had been butchered .Harold Faulkner recess choked it and regulated the barrel at improved cylinders.it shot a great pattern . He could only cut a small jug as the barrel was quite thin at the end . This was a long time ago.His daughter is a gunsmith now.

[Fellside]

2 hours ago, Velocette said:

I now have a second set of these fierce looking Brno 301 barrels also choked cylinder and cylinder. Whist I do use  the original cylinder/cylinder pair, to some effect on the right occasion I would like to have a tad more choke, 0.005" in at least one barrel of the new set and wondered if this can be achieved by jug choking. The barrel walls at the muzzle have plenty of meat on them so they should be safe to open out a little. Has anyone had this done, by whom, and were they happy with the result ?

Have you thought about just putting more shot in the pattern? An extra couple of grams would probably give you the 0.005” (equivalent) pattern % you’re after. For example - going from 30 gram to 32 gram….. or perhaps dropping a shot size to increase pellet count….?

[dipper]

I have used a BRNO sleet gun  always thought they had a bit of choke in them .was surprised at ranges I shot stuff at .Lot of sleet guns carried some choke .

[Stonepark]

The choke is in the same area as the porting, therefore a jug choke may not be possible as I am pretty sure the porting is cut after the chokes are machined.

 

As always, pattern both sets of barrels with a decent (high antimony) fibre clay cartridge at 40 yards and count strikes in 30 inch circle to check what patterns they actually throw.

You may find either or both pattern at cyl or skeet, IC or more but until you check, you are working from a position without full knowledge.

Only then should you consider any alterations to your set up which as noted above might be better by tuning the ammo, rather than the gun

 

Edited July 13, 2022 by Stonepark

[Walker570]

16 minutes ago, dipper said:

I have used a BRNO sleet gun  always thought they had a bit of choke in them .was surprised at ranges I shot stuff at .Lot of sleet guns carried some choke .

I had use of one of these or very similar back in the early '70s and it was said to be skeet and skeet but  I shot some  40  45yrd partridge which just folded using Eley 'blue' trap carrridges...probably 7s  long time ago to remember.  It was a gun I borrowed from a friend whilst mine was in for repair and he had to threaten me to get it back.

Cracking little gun.

18 minutes ago, Stonepark said:

The choke is in the same area as the porting, therefore a jug choke may not be possible as I am pretty sure the porting is cut after the chokes are machined.

 

As always, pattern both sets of barrels with a decent (high antimony) fibre clay cartridge at 40 yards and count strikes in 30 inch circle to check what patterns they actually throw.

You may find either or both pattern at cyl or skeet, IC or more but until you check, you are working from a position without full knowledge.

Only then should you consider any alterations to your set up which as noted above might be better by tuning the ammo, rather than the gun

 

Yes and measure the distance  don't guess it.  40 yrds is quite a long way when you look at it.

[wymberley]

If while patterning a TC barrel you get a 40% pattern, then when measuring the barrel it's odds on that there ill be a couple of thou' of choke present. You've already got the two best answers. If neither suits your needs, how long are the barrels and how long is the ported portion?

[Velocette]

Sorry for the delay answering. just watched a very exciting Tour de France mountain stage. Plenty to think about there before making any mechanical alterations. My bore gauge gave no sign of a choke restriction in any of the barrels but I'll check that. Cartridge selection is something I've started to try, using 30g 7 (Kranks) and 32g 6 Eley Pigeon HV but not on a pattern plate yet so absolutely no proper evidence at all yet, just a feeling that the pattern was a bit slack. I use Eley Pigeon Select in 30 g 6 as a base cartridge with the occasional Fiocchi TT1 28g 7.5 which does seem nearly right. I'll give a proper pattern test with these and some other similar cartridges and report back. Thanks for the help.

[Velocette]

5 hours ago, Stonepark said:

The choke is in the same area as the porting, therefore a jug choke may not be possible as I am pretty sure the porting is cut after the chokes are machined.

 

As always, pattern both sets of barrels with a decent (high antimony) fibre clay cartridge at 40 yards and count strikes in 30 inch circle to check what patterns they actually throw.

You may find either or both pattern at cyl or skeet, IC or more but until you check, you are working from a position without full knowledge.

Only then should you consider any alterations to your set up which as noted above might be better by tuning the ammo, rather than the gun

 

The bore of the ported/ventilated section of the barrel is quite a lot larger that the barrel I.D. so shouldn't interfere with any choke adjustments. However, could you recommend a high antimony clay cartridge to try in 28g 7.5 ? I have limited experience of target shooting and only use the Fiocchi TT1 type for the occasional straw bale shoot locally, purely for the fun of it. I agree that tuning the ammunition would be a far more sensible option. As an afterthought, I may try some steel cartridges where I am allowed to because it seems to be claimed that plaswad+steel do pattern more closely than fibre. This too would have to be pattern tested to check its veracity. Thanks for the advice.

[Stonepark]

I use Gamebore White Gold as my standard reference cartridge, but you should choose one you can get easily and locally.

 

Hull Pro fibre would be another.

 

 

[Scully]

I had to look up ‘jug choking’ ….and no, it’s very kind of you Wymberley, but I don’t need an explanation. Thankyou. 🙂

[wymberley]

13 hours ago, Scully said:

I had to look up ‘jug choking’ ….and no, it’s very kind of you Wymberley, but I don’t need an explanation. Thankyou. 🙂

Phew! that's a relief. 

[welshwarrior]

That porting will make any retro choking difficult, I think jug choke would be incredible hard.  
 

Teague can insert a permanently bonded sleeve into a barrel to add extra choke, they could possibly then recut the porting, at a guess.  

 

[wymberley]

8 hours ago, welshwarrior said:

That porting will make any retro choking difficult, I think jug choke would be incredible hard.  
 

Teague can insert a permanently bonded sleeve into a barrel to add extra choke, they could possibly then recut the porting, at a guess.  

 

And a fine job they make of it too boot. 

[Velocette]

Lots of good advice there which makes me think that mechanically adjusting the barrels is a non starter and I should do some testing with a variety of cartridges to get some tightening of the pattern in one set of the cylinder barrels. Its only a fancy but I do use two other guns choked at 5 and 15 thou which give lovely patterns out to 40yds with my favourite Eley Pigeon Select 30g No.6. I've got a couple of boxes of Gamebore White Gold, two boxes of Henry Kranks 30g No7 (Eley?) and some Imperial Game 28g No6 to try this week some time so its out with the survayors tape and the lining paper !

[Stonepark]

15 minutes ago, Velocette said:

Lots of good advice there which makes me think that mechanically adjusting the barrels is a non starter and I should do some testing with a variety of cartridges to get some tightening of the pattern in one set of the cylinder barrels. Its only a fancy but I do use two other guns choked at 5 and 15 thou which give lovely patterns out to 40yds with my favourite Eley Pigeon Select 30g No.6. I've got a couple of boxes of Gamebore White Gold, two boxes of Henry Kranks 30g No7 (Eley?) and some Imperial Game 28g No6 to try this week some time so its out with the survayors tape and the lining paper !

Good Luck!

Looking forward to hearing the results.

[TIGHTCHOKE]

Tulip Choke is another name, all do the same thing.

[Fil]

On 18/07/2022 at 21:15, TIGHTCHOKE said:

Tulip Choke is another name, all do the same thing.

It's Tula choke bud. Yes. Same. "Jug" choking or jug boring is an Americanism for back boring skeet chokes or barrels with no choke to get some choke back into the barrel. 

 

[wymberley]

37 minutes ago, Fil said:

It's Tula choke bud. Yes. Same. "Jug" choking or jug boring is an Americanism for back boring skeet chokes or barrels with no choke to get some choke back into the barrel. 

 

Don't worry, he is after all a bit of a petal. 

[Velocette]

On 18/07/2022 at 19:53, Stonepark said:

Good Luck!

Looking forward to hearing the results.

My word, its a lot of walking to and fro with sheets of unruly paper to do this pattern testing ! However, I am starting to see some light now. I tested at 30yds simply because its a reasonable decoying distance and it will give me some guidance as to the likely state of the pattern density a little further out which I will fine tune at a later date. The original cartridge which gave me no confidence was the Fiocchi Pigeon 32g No.6 but as I have none at the moment wasn't tested.

I shot 10 cartridges of each of the following types at 30 yds, listed according to their relative success or failure.

Hull Imperial Game. 28g No.6. ranged between 45 and 50%

Hull Imperial Game 30g no.6  ranged between 45 and 48%

Henry Krank (Eley) 30g No.7  gave an average of 38%

Eley Pigeon Select 30g No.6 gave an average of 43%

Gamebore White Gold 28g 7.5 gave an average of   41%

Eley HV Pigeon 32g No.6 gave an average of 33%

Given that all this is at 30yds and roughly the distance I would use this particular  barrel set at then I can only conclude that my limited and untested attempts with the Fiocchi cartridge gave a very misleading view and a lesson to all to pattern test before chasing other solutions to poor performance !  

I'm rather glad that the Hull cartridges seemed to work well as they are a favourite in my posh Baikal, choked at 5 and 15 thou and seem to knock everything out of the sky that I point it at. I'm not sue that I would like to pattern test that one for fear of finding something which knocks my confidence in it.

I'll take this gun with me on Saturday as a second gun and use it when the opportunity presents itself .                           

[Stonepark]

2 hours ago, Velocette said:

My word, its a lot of walking to and fro with sheets of unruly paper to do this pattern testing ! However, I am starting to see some light now. I tested at 30yds simply because its a reasonable decoying distance and it will give me some guidance as to the likely state of the pattern density a little further out which I will fine tune at a later date. The original cartridge which gave me no confidence was the Fiocchi Pigeon 32g No.6 but as I have none at the moment wasn't tested.

I shot 10 cartridges of each of the following types at 30 yds, listed according to their relative success or failure.

Hull Imperial Game. 28g No.6. ranged between 45 and 50%

Hull Imperial Game 30g no.6  ranged between 45 and 48%

Henry Krank (Eley) 30g No.7  gave an average of 38%

Eley Pigeon Select 30g No.6 gave an average of 43%

Gamebore White Gold 28g 7.5 gave an average of   41%

Eley HV Pigeon 32g No.6 gave an average of 33%

Given that all this is at 30yds and roughly the distance I would use this particular  barrel set at then I can only conclude that my limited and untested attempts with the Fiocchi cartridge gave a very misleading view and a lesson to all to pattern test before chasing other solutions to poor performance !  

I'm rather glad that the Hull cartridges seemed to work well as they are a favourite in my posh Baikal, choked at 5 and 15 thou and seem to knock everything out of the sky that I point it at. I'm not sue that I would like to pattern test that one for fear of finding something which knocks my confidence in it.

I'll take this gun with me on Saturday as a second gun and use it when the opportunity presents itself .                           

Thanks for putting these up. I assume you opened a cartridge of each type up and physically counted the pellets to enable calculation of the percentages?

The barrel set used appears to be at best cylinder but more likely reversed choked given pattern is 10% less than expected but if you are shooting 1 ⅛ of no9 at skeet in the 70's or 80's this would make sense.

The table below gives the percentage you should expect every 5 yards from the muzzle.

The Eley pigeon HV stands out as being particularly poorly and significantly worse than the cheaper Eley Select.

I suspect your Baikal will surprise you as I have yet to see an unmodified Baikal shoot a pattern less than it was supposed to be.

It is surprising what you learn from testing.

[wymberley]

14 hours ago, Velocette said:

My word, its a lot of walking to and fro with sheets of unruly paper to do this pattern testing ! However, I am starting to see some light now. I tested at 30yds simply because its a reasonable decoying distance and it will give me some guidance as to the likely state of the pattern density a little further out which I will fine tune at a later date. The original cartridge which gave me no confidence was the Fiocchi Pigeon 32g No.6 but as I have none at the moment wasn't tested.

I shot 10 cartridges of each of the following types at 30 yds, listed according to their relative success or failure.

Hull Imperial Game. 28g No.6. ranged between 45 and 50%

Hull Imperial Game 30g no.6  ranged between 45 and 48%

Henry Krank (Eley) 30g No.7  gave an average of 38%

Eley Pigeon Select 30g No.6 gave an average of 43%

Gamebore White Gold 28g 7.5 gave an average of   41%

Eley HV Pigeon 32g No.6 gave an average of 33%

Given that all this is at 30yds and roughly the distance I would use this particular  barrel set at then I can only conclude that my limited and untested attempts with the Fiocchi cartridge gave a very misleading view and a lesson to all to pattern test before chasing other solutions to poor performance !  

I'm rather glad that the Hull cartridges seemed to work well as they are a favourite in my posh Baikal, choked at 5 and 15 thou and seem to knock everything out of the sky that I point it at. I'm not sue that I would like to pattern test that one for fear of finding something which knocks my confidence in it.

I'll take this gun with me on Saturday as a second gun and use it when the opportunity presents itself .                           

YEP. Guidance is the operative word. Don't rely on tables in as much as for predictions for a greater range for a given cartridge when measured at, say, 30 yards. When measured again at, say, 40 yards it will in all probability be below par.

Looking at your figures, it may just pay to try the Fiocchi again if you get some as you might just find that they're innocent of all charges and the barrels are the guilty party.

Edited August 5, 2022 by wymberley

[Velocette]

Stonepark, after you mentioned the possibility of reversed choke I checked the bores of the barrel set I used, to a distance of about 6" from the muzzle and found that the last 2" were about 1.5 thou larger that the bore. This was measured with a comparator gauge and was the same in both barrels. I then checked the other barrel set, which I haven't pattern tested yet and found that they were exact cylinder right to the muzzle. Clearly there is more patterning to be done with this barrel set.

Wymberley. I will try the Fiocchi cartridges again because in other guns I've found them to be quite reasonable and perhaps this reversed choke situation is giving a misleading result and the barrels are indeed guilty !