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6 minutes ago, Rewulf said:

+1, I  thought it needs to be reasonably close in, at 35 yards it can be be difficult to discern where the centre of it is, depending on choke obviously.

Westward has said 35 yards, I said 40 - both OK. The possibility being that the OP might just see a smaller discrepency between the individual POI of the two barrels at that distance - as you point out, best to use the tightest choke available. He might just find that the storm reverts to teacup proportions and any discrepancy becomes acceptable.

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Our American cousins are totally anal about this stuff and they insist on an initial test at 13yds shooting from a bench rest and aiming like a rifle. This apparently tests barrel alignment and such but there's no point in convergence testing at anything other than 35yds or thereabouts.

None of this is pattern testing though;  it's all POA/POI testing. Pattern testing is done to test and compare different chokes and shells by shooting normally, gun mounted in the usual way and at whatever you think is a typical range at a pattern plate or cardboard sheet with a cross or spot marked on it and counting how many pellets strike within a 30" circle. Pattern testing can take a long time and is also a fair test to see if the gun shoots where you think you're pointing it.

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13 minutes ago, Jacko3275 said:

Read something about  16 yard just thought I’d do it at 20 as it’s a nice round figure ... poi does this not also give me what the pattern is like 

Quite often it pays to do one thing at a time. Where you have started is a barrel convergence test. Try it again at 40 yards. You can also do a pattern test in the same fashion - but be warned this has nothing to do with gun fit - just try what would be your preferred chokes at a preferred range in as many different configurations that you have the patience for. Six shots (from a previously fired barrel) per test and do not be tempted to discard any because they seem either unusually loose or tight.

That's my lot, my earlier remark about computers now applies with regards to the 16 yards (your eye is c1 yard from the muzzle so 1/16" error at the stock is one inch error at the 16 yards is the theory) and to put this into practise you need someone competent beside you to gain the most benefit.

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I use a laser cartridge bore sighter to check alignment, only need barrels which should be fixed (clamp, vice sandbag) on target, insert laser catridge in same position in both barrels (i. E. Don't rotate it between barrels) and mark location on target board, which should give a good idea of POI of both barrels

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4 hours ago, Jacko3275 said:

Read something about  16 yard just thought I’d do it at 20 as it’s a nice round figure ... poi does this not also give me what the pattern is like 

The 16 yards is for gun fit . As for every inch the center of the pattern is from your aim point on the target , the gun needs adjusting 1/ 16 of an inch per inch out .

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On 11/07/2019 at 19:42, Jacko3275 said:

Pattern tested my gun today  and the bottom barrel is around the centre of the target and the top barrel is probably 70/30 above the target used hull x comp 7.5  28g 65mm and hull pigeon 6 29g 70mm both had same results ... is it normal for both barrels to shoot different 

hello, that is why chokes are used or we would all be using shotguns with straight through tubes, your ATA should have open choke top/ tighter choke bottom barrel, hence why it is more centre target than top, interesting the 2 makes of cartridges come out with similar pattern, nothing wrong with Turkish made shotguns, 

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1 hour ago, oldypigeonpopper said:

hello, that is why chokes are used or we would all be using shotguns with straight through tubes, your ATA should have open choke top/ tighter choke bottom barrel, hence why it is more centre target than top, interesting the 2 makes of cartridges come out with similar pattern, nothing wrong with Turkish made shotguns, 

Is it not the other way round, top barrel being a tighter choke than the bottom?

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5 minutes ago, old'un said:

Is it not the other way round, top barrel being a tighter choke than the bottom?

hello, if you look at a  fixed  choke O/U top barrel is the more open choke, well mine have always been like that and i prefer the bottom barrel to be the tighter choke, look at side by sides ? as to why they make fixed choke shotguns this way i think you need to ask gunman,  

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20 minutes ago, oldypigeonpopper said:

hello, if you look at a  fixed  choke O/U top barrel is the more open choke, well mine have always been like that and i prefer the bottom barrel to be the tighter choke, look at side by sides ? as to why they make fixed choke shotguns this way i think you need to ask gunman,  

Interesting; I have 4 x o/u with fixed chokes.  All have the upper barrel tighter (by measurement, not patterning).  Of these, three are (as far as I know) as they left the factory.  Gun 4 has been worked on, though by a previous owner, so I don't know the details other than he had the chokes 'opened a bit'.

Gun 1, barrels 1 - Lower = cylinder  Upper = improved cyl

Gun 1, barrels 2 - Lower = quarter  Upper = half

Gun 2, - Lower = tight quarter  Upper = tight half

Gun 3,  - Lower = Improved cylinder  Upper = quarter

Gun 4, - Lower = tight quarter  Upper = tight half

 

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Well every U/O I have used (selective or non-selective) the bottom barrel fires first then top? One of the reasons for it firing that way is to reduce muzzle flip from the top barrel.

Side by side, its usually the right barrel first (less choke) then left barrel (more choke)

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30 minutes ago, oldypigeonpopper said:

hello, if you look at a  fixed  choke O/U top barrel is the more open choke, well mine have always been like that and i prefer the bottom barrel to be the tighter choke, look at side by sides ? as to why they make fixed choke shotguns this way i think you need to ask gunman,  

Based on the saying that, "choke is the work of the devil", he must have been in a right foul mood the day he invented multi-chokes and consequently I've always avoided them like the plague. Of all my guns either bought or altered, I have never specified which way around the chokes should be and they've always been tight on top and loose below.

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50 minutes ago, wymberley said:

Based on the saying that, "choke is the work of the devil", he must have been in a right foul mood the day he invented multi-chokes and consequently I've always avoided them like the plague. Of all my guns either bought or altered, I have never specified which way around the chokes should be and they've always been tight on top and loose below.

Unless you are shooting driven birds then a good O/U multi-choke setup is usually, bottom barrel first shot (less muzzle flip) and the barrel with the most choke, then top barrel second shot (barrel with the less choke).

The only problem with fixed chokes (O/U selective trigger) on driven birds you are forced to take the first shot with the top barrel (the one with more choke).

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13 minutes ago, old'un said:

Unless you are shooting driven birds then a good O/U multi-choke setup is usually, bottom barrel first shot (less muzzle flip) and the barrel with the most choke, then top barrel second shot (barrel with the less choke).

The only problem with fixed chokes (O/U selective trigger) on driven birds you are forced to take the first shot with the top barrel (the one with more choke).

I think it must be me and my memory as I no longer shoot driven. However, I always figured (I think) that your opening sentence should have started with, "If" and not, "Unless". This does assume though that you're taking birds out front. As for the O/U selective trigger, see the S56E thread running on Guns and Equipment. However, back along I used one gun for everything so muddled through with the conventional choke arrangement.

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Sorry, I was trying to point out the advantage of multi-choke in an O/U for driven birds, guess I should have highlighted… “he must have been in a right foul mood the day he invented multi-chokes”

 

Found an old PW thread that also talks about barrel selection and chokes….it covers more on the subject of which barrel on an O/U is the one that is usually fired first and which barrel has more choke…https://forums.pigeonwatch.co.uk/forums/topic/68262-which-barrel-first/

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23 hours ago, Stonepark said:

I use a laser cartridge bore sighter to check alignment, only need barrels which should be fixed (clamp, vice sandbag) on target, insert laser catridge in same position in both barrels (i. E. Don't rotate it between barrels) and mark location on target board, which should give a good idea of POI of both barrels

Which unfortunately can go to pot when this static test is replaced by a dynamic one when the gun is actually fired.

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22 hours ago, oldypigeonpopper said:

hello, if you look at a  fixed  choke O/U top barrel is the more open choke, well mine have always been like that and i prefer the bottom barrel to be the tighter choke, look at side by sides ? as to why they make fixed choke shotguns this way i think you need to ask gunman,  

hello, perhaps i should check my old franchi, anyway my new O/U i have the top open choke and bottom choked as i prefer that way

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25 minutes ago, oldypigeonpopper said:

hello, perhaps i should check my old franchi, anyway my new O/U i have the top open choke and bottom choked as i prefer that way

On your old franchi (fixed choke) is it selective trigger, if so which barrel have you set to fire first?

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16 minutes ago, old'un said:

On your old franchi (fixed choke) is it selective trigger, if so which barrel have you set to fire first?

hello, no it is a double trigger model, fixed choke 1/4 1/2 ideal hide gun, i will have a look and see which barrel is choked 1/2 ,  but i am trying to get use to my new O/U Yildiz with single selective, 

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4 minutes ago, oldypigeonpopper said:

hello, no it is a double trigger model, fixed choke 1/4 1/2 ideal hide gun, but i am trying to get use to my new O/U Yildiz with single selective, 

So on your old double trigger franchi which barrel do you fire first?

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