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20 Bore Help


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Please.

Both my barrels, give or take, at 0.632/0.630" equate to the 16.0 stamped on my Beretta. I don't know but suspect that the 2 and 4 spots are as per - 3/4 and 1/4 - .605 and .615 respectively. Questions: Would those chokes be right and what would you expect the figures to be for Imp and I/2?

I have to say that the 0.632" is alien to me for 20 bore but this does equate to the 16 - obviously mms - stamped on the barrels.

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As you say, .630 is near bang on 16 mm.  Choke is best (in my view) described as 'estimated' based on barrel measurements - because really it is the effect it has on pattern that is important.  For 'estimating' purposes based on the constriction compared to the parallel part of the bore (taken as .630);

  • 3/4 (nominally 21 thou constriction) would be about .609 based on .630 parallel part bore and similarly
  • 1/4 (nominally 7 thou constriction) would be .623. 

Based on this - your gun at .605 (25 thou constriction) and .615 (15 thou constriction) seems more like almost full and 1/2 (a bit tighter than you mention)

  • 1/2 would be approx .616 (14 thou constriction) in the choked area - and
  • Imp about .626 (4 thou constriction). 

Figures from here https://www.theyorkshiregent.com/shooting/shotgun-chokes-explained-guide-markings-sizes-patterns/

If you wish to know accurately what pattern you are getting, the pattern plate is really the only way, and of course it will vary somewhat by cartridge.

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1 minute ago, JohnfromUK said:

If you wish to know accurately what pattern you are getting, the pattern plate is really the only way, and of course it will vary somewhat by cartridge.

Amen to that!  :good:

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Continental choke boring dose not equate directly to those we are used to in the UK .Not all makers used the same standard . Since retirement I have disposed of most of my lists of specific bore ,and choke sizes , but in general terms they are largely  based on increments of .2 mm or .008" . 

The choking on small bores are different to those on a 12 bore , so full choke on a twenty bore would be .025/.030" dependent on maker .

Continental gunmakers tended to use .622"/626" or 15.8mm/15.9 rather than the .615" as a standard used in the UK for 20 bores .

Spanish chokes were different and used between sizes so a Spanish full choke on a 12 bore could be  be 0.9mm to 1.1mm or  .036"/.044"constriction 

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I bought one of those cheap £5 choke gauges. I have read they aren’t worth it as not accurate.  
 

In my silver pigeon and my Teague Mobil chokes it matches up exactly to the marked constriction. 
 

 

I tried it on my Maxus chokes yesterday. 
 

cyl showed up as Bore. 
 

1/4 showed up as Cyl. 
1/2 showed up as Cyl. 
3/4 showed up as Cyl. 
Full shower up as 1/2. 
 

work that one out 🤷‍♂️

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55 minutes ago, JohnfromUK said:

As you say, .630 is near bang on 16 mm.  Choke is best (in my view) described as 'estimated' based on barrel measurements - because really it is the effect it has on pattern that is important.  For 'estimating' purposes based on the constriction compared to the parallel part of the bore (taken as .630);

  • 3/4 (nominally 21 thou constriction) would be about .609 based on .630 parallel part bore and similarly
  • 1/4 (nominally 7 thou constriction) would be .623. 

Based on this - your gun at .605 (25 thou constriction) and .615 (15 thou constriction) seems more like almost full and 1/2 (a bit tighter than you mention)

  • 1/2 would be approx .616 (14 thou constriction) in the choked area - and
  • Imp about .626 (4 thou constriction). 

Figures from here https://www.theyorkshiregent.com/shooting/shotgun-chokes-explained-guide-markings-sizes-patterns/

If you wish to know accurately what pattern you are getting, the pattern plate is really the only way, and of course it will vary somewhat by cartridge.

P attern plate is good but simply going and shooting at things is best and forget the figures !!!

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13 minutes ago, Lloyd90 said:

I bought one of those cheap £5 choke gauges. I have read they aren’t worth it as not accurate.  
In my silver pigeon and my Teague Mobil chokes it matches up exactly to the marked constriction. 
I tried it on my Maxus chokes yesterday. cyl showed up as Bore. 1/4 showed up as Cyl. 1/2 showed up as Cyl. 3/4 showed up as Cyl. Full shower up as 1/2. work that one out 🤷‍♂️

The only way to accurately check you choke performance is on the pattern plate, ANYTHING else is just an indication.

Measuring the bore and measuring the choke constriction accurately is next best.

But actually firing 10 shots through your chosen choke and a known distance will give you the right answer.

Or as Mat says, just go out and shoot!

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All cartridge manufacturers use pattern plates in research and development for all their cartridge loads.

I think we can all see that there is a message there.

This has been discussed soooo manty times over the years.

Every single gun behaves differently with different brands, load weight, shot size, chokes, which is why there is only ever one way to determine patterns.

Most people would be amazed at how well open chokes perform with certain loads especially with a 20 guage.

 

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1 hour ago, Shotkam said:

All cartridge manufacturers use pattern plates in research and development for all their cartridge loads.

I think we can all see that there is a message there.

This has been discussed soooo manty times over the years.

Every single gun behaves differently with different brands, load weight, shot size, chokes, which is why there is only ever one way to determine patterns.

Most people would be amazed at how well open chokes perform with certain loads especially with a 20 guage.

 

Agreed,last week three of us had a 20b shoot as a new 725 20b had been purchased by a friend. He broke every target shown ,several of the tougher ones being from the previous 100 reg comp....he had skeet & 1/4 choke in it and used a mix of Hull Pro`s and Eley CT 24g fibre....

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Cheers, All.

That will teach me to buy a gun bored differently to the vast majority of others. I was hoping to avoid it, but the pattern plate it'll have to be.

I've known what I've been doing since the 80s in order to maintain as far as possible a clear conscience, but also test myself a little. A tip, do not grow
old. If you find it impossible not to do so, do not get rheumatoid arthritis (RA). Should you slip up, avoid a treatment which does its best to stop you 
breathing and ultimately results in seropositive RA associated Interstitular Lung Disease. A run of the mill RA treatment caters for the disease itself but
 is not a painkiller and you may well need some help in this respect. Just pray that you're not one of the 60% of the population that don't take kindly to
codeine. I have failed on all counts.

As previously mentioned, I now have a W&S 12 which suits me nicely. Or so I thought at the time. I was going to have it opened up - it's survived in the 
original 1/2 by Full since '62 - and fortunately I haven't done so yet as now it might have needed doing twice. Yesterday, not having been out for a while,
it became obvious I've also gained weight on my fingers - or more accurately, they've swollen - as I hit the bruised finger problem. - even more swollen 
now! I've already ordered the protector and if it works as it should, then we'll be looking at Imp by 1/2. As for the Beretta, a decision to be made after 
the plate. All this because I'm finally going to have to bite the bullet and reduce my range.

All in all not a good week as it looks as though the promised Anschutz delivery for July isn't.

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23 hours ago, Shotkam said:

All cartridge manufacturers use pattern plates in research and development for all their cartridge loads.

I think we can all see that there is a message there.

This has been discussed soooo manty times over the years.

Every single gun behaves differently with different brands, load weight, shot size, chokes, which is why there is only ever one way to determine patterns.

Most people would be amazed at how well open chokes perform with certain loads especially with a 20 guage.

 

I agree with this last sentence completely, I use the two most open chokes that came with my 20b Beretta for all my shooting. With 26gm of No7 it works really well.  

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2 minutes ago, shalfordninja33 said:

I agree with this last sentence completely, I use the two most open chokes that came with my 20b Beretta for all my shooting. With 26gm of No7 it works really well.  

I’ve been telling folk for half a century but most of them are too obsessed with tight chokes and consequently don’t hit so much.

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4 hours ago, shalfordninja33 said:

I agree with this last sentence completely, I use the two most open chokes that came with my 20b Beretta for all my shooting. With 26gm of No7 it works really well.  

Yep, based on the premiss that the shot is accurately placed, then any cartridge/gun combination will work really well if sufficient pellets each having sufficient energy arrive at the requisite location at the same time. As we're talking choke, we'll assume sufficient energy. Too many pellets - apart from damaged meat -  means that things are not working really well and that there's too much choke and the by-product is that we're making things unnecessarily difficult for ourselves. On the other hand, too few is equally detrimental - I would say more so as the chances of wounding our quarry increase. Back along everybody and their granny lived by the 3 pellet plus 10% for stringing rule, but then, thirty yards was a long/high bird. It would really help if the open choke advocates explained their current methodology so we can all benefit. 

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31 minutes ago, wymberley said:

It would really help if the open choke advocates explained their current methodology so we can all benefit. 

No great secret; the vast majority of my shooting is at 'normal farm shoot style' ranges, probably being 25 to 35 yards - and so my current (everything between Imp and 1/2) depending on the gun works just fine with an appropriate (1 ounce typically), always fibre wad cartridge.

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35 minutes ago, wymberley said:

Yep, based on the premiss that the shot is accurately placed, then any cartridge/gun combination will work really well if sufficient pellets each having sufficient energy arrive at the requisite location at the same time. As we're talking choke, we'll assume sufficient energy. Too many pellets - apart from damaged meat -  means that things are not working really well and that there's too much choke and the by-product is that we're making things unnecessarily difficult for ourselves. On the other hand, too few is equally detrimental - I would say more so as the chances of wounding our quarry increase. Back along everybody and their granny lived by the 3 pellet plus 10% for stringing rule, but then, thirty yards was a long/high bird. It would really help if the open choke advocates explained their current methodology so we can all benefit. 

 

1 minute ago, JohnfromUK said:

No great secret; the vast majority of my shooting is at 'normal farm shoot style' ranges, probably being 25 to 35 yards - and so my current (everything between Imp and 1/2) depending on the gun works just fine with an appropriate (1 ounce typically), always fibre wad cartridge.

For me it's fairly straight forward in that the vast majority to shooters over estimate range and more importantly their ability. (me included) As if using more choke with a heavier payload makes up for the lack of the latter. As @JohnfromUK says a bird at 25 to 35 yards will more that likely be comfortably despatched with little if any choke and a moderate payload. From my personal experience on Essex 'normal farm shoot style' ranges it's perfectly adequate, dead is dead with very few wounded, therefore I don't see the need to use a heavier load or tighter chokes, it works.   

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6 minutes ago, shalfordninja33 said:

For me it's fairly straight forward in that the vast majority to shooters over estimate range and more importantly their ability. (me included) As if using more choke with a heavier payload makes up for the lack of the latter. As @JohnfromUK says a bird at 25 to 35 yards will more that likely be comfortably despatched with little if any choke and a moderate payload. From my personal experience on Essex 'normal farm shoot style' ranges it's perfectly adequate, dead is dead with very few wounded, therefore I don't see the need to use a heavier load or tighter chokes, it works.

Agree.  40+ yards is not a normal shot for me.  If it is a pricked bird - then I would have a go, but it isn't something I would either do or try to do generally.  It isn't needed in my shooting days, and IF I was to use large high performance loads and tight chokes (such as suited to a Devon style 'high bird shoot') - then I would either have to leave the vast majority of what would come over my peg, or accept a lot of the birds would be badly 'shot up'.  Ours birds are mostly at more 'normal' ranges.  Horses for courses and a modest load and open(ish) choke suits what I do.

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Posted (edited)

Can't fault the last few posts - except that is, for a "pricked bird" as there's no such thing, it's wounded - so let me take another tack. Everyone is saying 'my birds' - what birds are those? We've ascertained that apparently 30 yards is nowhere near a high bird so let's step it up a bit to the proverbial 40 and as this is Pigeon Watch, let's go with that species and with lead shot. To be reasonably certain of a clean kill as far as it's possible so to do what gun choke/cartridge load - I think as we can all possibly accept that any of the more popular choices from 7s, 6&1/2s and 6s will all have sufficient energy at that distance we can simply look at pellet count -  would you select? For those whom 40 yards is excessive, just select your preferred maximum?

eg: True Cylinder with 2oz of BBs at 40 yards

Edited by wymberley
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22 minutes ago, wymberley said:

except that is, for a "pricked bird" as there's no such thing, it's wounded

OK, a pricked bird is a wounded bird.  I accept that.  We have all seen a bird clearly hit, but not down - and to take a shot at more than one's comfortable range seems to me 'in order' in that case.

 

24 minutes ago, wymberley said:

I think as we can all possibly accept that any of the more popular choices from 7s, 6&1/2s and 6s will all have sufficient energy at that distance we can simply look at pellet count -  would you select? For those whom 40 yards is excessive, just select your preferred maximum?

I don't do my shooting on a calculator - or from tables.  I don't think of the range of each bird in yards, metres, or whatever;  What (I think) runs through my mind is:

  • Is it safe?,
  • is it 'on the quarry list for the day'?
  • Is it 'my bird'?,
  • is it too close?,
  • is it too far? 
  • is it hit and wounded by another gun? 

Those are the sort of questions that run through my mind.  For the record, I use either 15/16 oz or 1 oz of no 6 through anything between Improved and 1/2 choke - not chosen specifically - simply - those are what are in my guns that I would pick for a day game shooting at home (or elsewhere where I have attended).  I am very comfortable with the combination I use for the shooting I do.

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14 minutes ago, JohnfromUK said:

OK, a pricked bird is a wounded bird.  I accept that.  We have all seen a bird clearly hit, but not down - and to take a shot at more than one's comfortable range seems to me 'in order' in that case.

 

I don't do my shooting on a calculator - or from tables.  I don't think of the range of each bird in yards, metres, or whatever;  What (I think) runs through my mind is:

  • Is it safe?,
  • is it 'on the quarry list for the day'?
  • Is it 'my bird'?,
  • is it too close?,
  • is it too far? 
  • is it hit and wounded by another gun? 

Those are the sort of questions that run through my mind.  For the record, I use either 15/16 oz or 1 oz of no 6 through anything between Improved and 1/2 choke - not chosen specifically - simply - those are what are in my guns that I would pick for a day game shooting at home (or elsewhere where I have attended).  I am very comfortable with the combination I use for the shooting I do.

Pricked: Well said, John, I wasn't having a go. Way back we could get away with it and did, but now we have to recognise that we're not fooling anybody and particularly not the antis, WJ, et al and we have to accept the responsibility for our actions.

Shooting: You have an invitation for a woodcock shoot where you can expect to be taking shots at a maximum of some 40 yards. It's fibre wad only. This is a chance of a lifetime as a successful day will lead to further invites so you would be expected to shoot at the maximum range. Can that encourage you to answer the question?

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Just now, wymberley said:

I wasn't having a go.

Not taken that way either.  Just a phrase I have used for 50 years!

Two (genuine) points; first I don't shoot woodcock (anymore) in fact our shoot is no woodcock allowed - hence (partly) the question about the allowed quarry list)- and second I doubt I would put my gun up on a woodcock at 40 yards.  A woodcock at a true 40 yards looks TINY.  I might not even see it!

Next, I only have (in my normal game guns, being a mix of Imp, 1/4 and 1/2 from which to choose. 

I do have one multichoke gun (bought second hand) and I believe it has 3/4 and full available though I have never changed the chokes in it.  I do have an additional set of barrels in full and extra full for one gun, but have never used them either (and doubt I ever will).  So - what would I pick?  Probably an AyA No 1 (6 3/4 lbs), choked (and I had to look this up) nominally about 1/4 and 1/2.  Patterns evenly with Hull Imperial Game 1 oz Fibre.  I would probably use my usual 1 oz No 6.  Simply - I am accustomed to what I use -and know fairly well how it performs at the ranges I am used to.  I woukd pick my birds to shoot what I feel comfortable with.  I have not been on a shoot where I am expected to take the majority of shots at 40 yards or so (some claim not to shoot under 40 yards) - and would do poorly under those circumstances.  I have no practice and it is well outside my comfort zone.

I cannot answer better (or more truthfully) than that!

Two reasons for not using my either my one multichoked gun - or the full and extra full barrels. 

  1. they are not what I would choose for woodcock anyway (both being on the heavy side)
  2. I would expect the majority of shots I woukld take to be well inside 40 yards - and heavy choke is not suited to that (in my view).
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25 minutes ago, JohnfromUK said:

Not taken that way either.  Just a phrase I have used for 50 years!

Two (genuine) points; first I don't shoot woodcock (anymore) in fact our shoot is no woodcock allowed - hence (partly) the question about the allowed quarry list)- and second I doubt I would put my gun up on a woodcock at 40 yards.  A woodcock at a true 40 yards looks TINY.  I might not even see it!

Next, I only have (in my normal game guns, being a mix of Imp, 1/4 and 1/2 from which to choose. 

I do have one multichoke gun (bought second hand) and I believe it has 3/4 and full available though I have never changed the chokes in it.  I do have an additional set of barrels in full and extra full for one gun, but have never used them either (and doubt I ever will).  So - what would I pick?  Probably an AyA No 1 (6 3/4 lbs), choked (and I had to look this up) nominally about 1/4 and 1/2.  Patterns evenly with Hull Imperial Game 1 oz Fibre.  I would probably use my usual 1 oz No 6.  Simply - I am accustomed to what I use -and know fairly well how it performs at the ranges I am used to.  I woukd pick my birds to shoot what I feel comfortable with.  I have not been on a shoot where I am expected to take the majority of shots at 40 yards or so (some claim not to shoot under 40 yards) - and would do poorly under those circumstances.  I have no practice and it is well outside my comfort zone.

I cannot answer better (or more truthfully) than that!

Two reasons for not using my either my one multichoked gun - or the full and extra full barrels. 

  1. they are not what I would choose for woodcock anyway (both being on the heavy side)
  2. I would expect the majority of shots I woukld take to be well inside 40 yards - and heavy choke is not suited to that (in my view).

Yep, Naturally, a more open choke for the shorter ranges would complement the tighter choke for the 40 yards. Your 1oz of No 6 through 1/2 choke would be good for 30-35 yards. 1&1/16oz of 7s and 3/4 would give you the 40 yards complemented perhaps by 1/4 for the more usual range.

As an aside, for pigeon your combination would give you some 35 yards and for the 7s, 45. If 35 yards was deemed sufficient, I'd settle for 1 oz of 7s and IC. Handy thing choke, it's there to be used.

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8 minutes ago, wymberley said:

Handy thing choke, it's there to be used.

Most of my choice of hardware is fixed choke, and between Imp and 1/2.  (A mix of Imp and 1/4, 1/4 in both, and 1/4 and 1/2)

I do have (as said earlier) one multichoke with a total of 6 inserts I think (never changed then, though do take them out for cleaning) - and two guns with 2 sets barrels, my S57 Beretta has either "Skeet" (two very near cylinder barrels) or "Game" (at nominally 1/4 and 1/2) and an AyA with two sets, one both 1/4, the other full and extra full (never used).

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