How much smaller is a 410/28 bore pattern?

[Gungoesbang]

So I have a few 12 bores of different guises, and a 20 bore o/u. However, I have an itch for a tiny, light 410 or 28 bore side by side. I don’t find the 20 bore too much worse than the 12 - maybe 10% lower scores on average. However, seen there are 410 championships and seen people struggling online - just worried I won’t hit anything at all! Would I be better off just getting a 20 sxs? 
Also is 28 bore going to be able to cope with steel shot, as in my understanding 410 won’t really? 

[Ultrastu]

I have 12 20 and .410 and if I put a 1/2 choke in all 3 and shoot at the same distance say 25 yds the patterns are basically the same size .obviously  the 18 grm load of the .410   has less pellets so density is lower than a 28 grm 12 or 20 b but the size is the same so it's  just as easy /hard to hit a 25 yd clay /bird with a .410 as it is with a 12 b 

The difference  comes when you move out to 35 yd plus and your patterns  are still the same size but the .410 pellet density isn't sufficient  to consistently break clays or kill birds  .

When I go to the clay ground I use my ou .410  it's more enjoyable  (after all that why I'm there ) and as long as I only shoot at targets up to 35 yds I can break them just fine .

[Ultrastu]

The main difference  in 12 /20 and .410 is that choke makes a bigger difference  on the bigger bores .

So when you swap the choke from cylinder to full on a 12 b there is a huge pattern spread difference at your chosen range . With a.410 there is virtually  no difference  hence why multi choke .410s aren't so common, and the guns that do have them are mainly for show .

[Stonepark]

7 hours ago, Gungoesbang said:

So I have a few 12 bores of different guises, and a 20 bore o/u. However, I have an itch for a tiny, light 410 or 28 bore side by side. I don’t find the 20 bore too much worse than the 12 - maybe 10% lower scores on average. However, seen there are 410 championships and seen people struggling online - just worried I won’t hit anything at all! Would I be better off just getting a 20 sxs? 
Also is 28 bore going to be able to cope with steel shot, as in my understanding 410 won’t really? 

 

No matter what bore you have choke serves the same function. As choke is a measurement based on the percentage of pellet strikes within a 30 inch circle at a chosen range.Full choke for a 12 bore will give a pattern spread exactly the same as a full choke 410, likewise 3\4, 1\2, 1\4, Cyl.

 

What is different is pattern density as 12 bore (28g no 7.5) starts off with 400 pellets, whilst the 410 (18g no7.5) starts off with 256 pellets.

 

The secret with 410 is to realise that as you are limited by total load, you need to keep the pellets small to maintain density.  No7 is the largest pellet you need (bar certain specialist loads) and 18g of no7 will kill to 35 yards, clays, vermin or game.

 

The reason most struggle is using too large a pellet and then too tight a choke to try to compensate for the lack of pellets.

Edited March 24 by Stonepark
Missed 7 out

[Ultrastu]

1 hour ago, Stonepark said:

No matter what bore you have choke serves the same function

Well that's the theory at least  

The reality is somewhat different  .

A .410 has all its pellets stacked in a long thin column in the cartridge  and there are probably around 6 pellets across the width of it  .compare that to a 12 b where you have maybe 20 - 25 pellets across the width in the cartridge  and hence in the bore as it passes through the choke  the choke constriction  helps force these 25 pellets together holding them together for a longer range  .the same doesn't work so well with the 6 pellets across in the .410 choke  .this is why the constriction  difference between full and cylinder  in .410 is very slight  and much more in 12b as it works much better in 12 than .410  .

 

[enfieldspares]

1 hour ago, Stonepark said:

 

No matter what bore you have choke serves the same function. As choke is a measurement based on the percentage of pellet strikes within a 30 inch circle at a chosen range.Full choke for a 12 bore will give a pattern spread exactly the same as a full choke 410, likewise 3\4, 1\2, 1\4, Cyl.

 

What is different is pattern density as 12 bore (28g no 7.5) starts off with 400 pellets, whilst the 410 (18g not.5) starts off with 256 pellets.

 

The secret with 410 is to realise that as you are limited by total load, you need to keep the pellets small to maintain density.  No7 is the largest pellet you need (bar certain specialist loads) and 18g of no7 will kill to 35 yards, clays, vermin or game.

 

The reason most struggle is using too large a pellet and then too tight a choke to try to compensate for the lack of pellets.

This. Always was this. Nothing has changed save across all bores crimp closures eliminating the old "overshot wad" and modern plastic full enclosure wads and quality shot may give some improvement in usable pellets with less "flyers".

[London Best]

3 hours ago, Stonepark said:

 

No matter what bore you have choke serves the same function. As choke is a measurement based on the percentage of pellet strikes within a 30 inch circle at a chosen range.Full choke for a 12 bore will give a pattern spread exactly the same as a full choke 410, likewise 3\4, 1\2, 1\4, Cyl.

 

What is different is pattern density as 12 bore (28g no 7.5) starts off with 400 pellets, whilst the 410 (18g not.5) starts off with 256 pellets.

 

The secret with 410 is to realise that as you are limited by total load, you need to keep the pellets small to maintain density.  No7 is the largest pellet you need (bar certain specialist loads) and 18g of no7 will kill to 35 yards, clays, vermin or game.

 

The reason most struggle is using too large a pellet and then too tight a choke to try to compensate for the lack of pellets.

Everything else in your post is correct, but there are NOT 256 pellets in 18g No.5.

[Stonepark]

2 hours ago, London Best said:

Everything else in your post is correct, but there are NOT 256 pellets in 18g No.5.

Apologies, must have missed 7 (and hit T instead) before the decimal point

Edited March 24 by Stonepark

[Stonepark]

4 hours ago, Ultrastu said:

Well that's the theory at least  

The reality is somewhat different  .

A .410 has all its pellets stacked in a long thin column in the cartridge  and there are probably around 6 pellets across the width of it  .compare that to a 12 b where you have maybe 20 - 25 pellets across the width in the cartridge  and hence in the bore as it passes through the choke  the choke constriction  helps force these 25 pellets together holding them together for a longer range  .the same doesn't work so well with the 6 pellets across in the .410 choke  .this is why the constriction  difference between full and cylinder  in .410 is very slight  and much more in 12b as it works much better in 12 than .410  .

 

Choke is a nominal constriction of the bore to produce a certain pattern width and density on a pattern plate at a certain range.

Full choke, whether 12b, 20b, 410 or otherwise is a constriction of approximately 11% in area of the bore.

In 12b this equates to approx 40thou, in 410 it equates to approx 22 thou.

The nominal choke does not care about the number of pellets!

 

The best patterns are produced by round pellets which are stable as they exit the muzzle. If this stability is disturbed by damaged pellets or unstabilised pellets, you get #### patterns.

How a gun chokes is not just due to the constriction of the choke, the pressure, forcing cones, lead hardness,  choke constriction, choke length, choke stabilisation area all have an impact.

Unlike the 12 bore where the large diameter bore (in relation to the shot diameter) means constriction is often the most important and the others are less significant, in the 410 due to the small bore to shot diameter ratio, these others come into play and can be significant.

 

A 410 with a high pressure loading, shooting soft lead with short, rough forcing cones, short choke with no stabilisation area, may indeed pattern like #### and it may not matter if it is cyl or full choked because 100% of the shot will be damaged by pressure, forcing cones and choke and spray out of the gun.

On the other hand a 410 operating at reasonable (high 12b but moderate 410) pressure, with hard shot, 3 inch forcing cones, and good chokes which have at least 1 inch of post choking stabilisation  will produce excellant patterns no different in quality from a 12 bore.

 

 

7 hours ago, Ultrastu said:

The main difference  in 12 /20 and .410 is that choke makes a bigger difference  on the bigger bores .

So when you swap the choke from cylinder to full on a 12 b there is a huge pattern spread difference at your chosen range . With a.410 there is virtually  no difference  hence why multi choke .410s aren't so common, and the guns that do have them are mainly for show .

This really is the worst post I have seen regarding the 410 and should be removed for it's complete inaccuracy!

[enfieldspares]

1 hour ago, Stonepark said:

 

The nominal choke does not care about the number of pellets!

 

Again. This. A gun has its choke bored to produce a certain percentage of pellets at a set distance. Now in one gun and in one of the barrels of that gun that may be a  20 thousandths of an inch constriction. In a different gun that may mean a 18 thousandths of an inch and in another 22 thousandths of an inch constriction. That a nominal choke of 20 thou may be according to the tables in the back of the Eley Diary "half" choke is as said irrelevant. The OP quoted is correct.

Now what that then sometimes means is that as the nominal choke is irrelevant some may, and wrongly say, that to produce a 50% pellet count that as the .410" they are using as an example is bored to 18 thou of choke. Whereas as the 12 bore being compared is bored to 20 thou of choke and produces a 50% pellet count. They then claim that this evidences that a .410" needs to be be bored to a less tight choke to produce what a large bore gun does with a more less tight choke.

But that is not how choke is correctly measured. It is measured not by it nominal constriction but by its pattern. The nominal constriction gives a starting point to approach when boring the chokes of a gun but only the results on the pattern plate show its true degree of choke. Asking for 20 thou of choke in a barrel is not the same as asking for that barrel to be bored half choke.

The 20 thou may be the nominal but the definitive is, and is always, the shot count percentage in the pattern. So yes maybe a .410" needs less constriction than does a 12 bore but the boring constriction does not define the choke. It is the pattern on the pattern plate that defines the choke. That is the master.

The constriction is its servant. It is the master that dictates - as quarter or half or three-quarter or full - what we call the degree of choke a gun has and not any nominal boring. We can say yes that a gun has 20 thou of choke and, by happy fortune, that may indeed give us the percentage of pellets on the pattern at forty yards that is known as "half choke". But that does not mean that 20 thou does in all guns produce a half choke pattern

So to repeat. The nominal choke (as defined in thousandths of an inch) "does not care about the number of pellets".

That nominal choke is merely is a reference about which on one side or the other a gun might then when fettled and finished might produce a half choke pattern on a pattern plate. In the same way that the angle or "o'clock" position of the needle on a dial type rev counter in a motor vehicle does not always match the angle or "o'clock" position of the needle on the dial type speedometer alongside it. 

Edited March 25 by enfieldspares

[Fellside]

18 hours ago, Gungoesbang said:

So I have a few 12 bores of different guises, and a 20 bore o/u. However, I have an itch for a tiny, light 410 or 28 bore side by side. I don’t find the 20 bore too much worse than the 12 - maybe 10% lower scores on average. However, seen there are 410 championships and seen people struggling online - just worried I won’t hit anything at all! Would I be better off just getting a 20 sxs? 
Also is 28 bore going to be able to cope with steel shot, as in my understanding 410 won’t really? 

Lots of good insights above. However, one of the key reasons why people often struggle with a 410 has little to do with ballistics, but gun weight. They have all of their timings and muscle memory etc typically tuned to a 7 1/2 lb 12 bore O/U - then pick up a 5lb 410 which ‘rushes to a stop’ all too easily. It takes a while to become familiar with this little garden cane, but when our brain ‘recalibrates’ so to speak, the 410 can become a magic wand and is a great joy to shoot. My advice is to buy one that fits (properly) and just enjoy getting used to it. 

Re chokes and cart’s, I know everyone has their favourite formula, but here’s mine for what it’s worth:

Eley Trap 14 gram 7 1/2 for clays 

Hull High Pheasant 18 gram 6 for pigeons and driven. 

Both through cylinder and quarter.

I find the unchoked barrel is efficient from about 15 to 25 yards and the choked barrel out to about 35 yards. 

Hope that helps. 

[Ultrastu]

So a new utube vid out today .field sport with speed.   He choke tests a kofs .410 from skeet to full at 30 yds and finds there is no difference in pattern size at all between them .confirming exactly  what I said above  .but hey I know nothing eh ? .hull high pheasant  18 grm no7 fibre  exactly the same cart I prefer to use .

Edited March 26 by Ultrastu

[Fargo]

https://youtu.be/Cs0-56lOYfY?si=1ZfSmqzgqf4Ba_BG

[Ultrastu]

Thank you  I can't do links .much appreciated 

[wymberley]

54 minutes ago, Ultrastu said:

So a new utube vid out today .field sport with speed.   He choke tests a kofs .410 from skeet to full at 30 yds and finds there is no difference in pattern size at all between them .confirming exactly  what I said above  .but hey I know nothing eh ? .hull high pheasant  18 grm no7 fibre  exactly the same cart I prefer to use .

Do you believe that the video reflects an acceptable standard for a pattern test?

[Ultrastu]

No I think 3 - 5 shots per cartridge  /choke would have been a bit better than a single shot per choke  .but it clearly shows that not much is changing between chokes even with just 1 shot each . I accept all of stoneparks comments above  including where he says basically if the chokes are of poor quality (not well designed ) they will produce patterns with very little difference  and I guess kofs make and fit these chokes  on there .410 s .

I wonder how precise a very good quality choke has to be on a quality gun to produce excellent patterns that we would expect from cylinder  through to full .in .410 ? 

Maybe it's just very hard to reproduce pattern size consistency from a .410 compared to 12b ? 

 

Edited March 26 by Ultrastu

[Stonepark]

2 hours ago, Ultrastu said:

So a new utube vid out today .field sport with speed.   He choke tests a kofs .410 from skeet to full at 30 yds and finds there is no difference in pattern size at all between them .confirming exactly  what I said above  .but hey I know nothing eh ? .hull high pheasant  18 grm no7 fibre  exactly the same cart I prefer to use .

 

As noted above in worse case scenario......., Kofs gun (inexpensive) with short forcing cones, high pressure cartridges, soft lead and very short multi chokes with no stabilisation zone, damages pellets and sprays patterns, hence changing chokes making little difference as no matter the choke the pellets are already ******** so patterns are poor and inconsistent across the board

Edited March 26 by Stonepark

[Stonepark]

25 minutes ago, Ultrastu said:

I wonder how precise a very good quality choke has to be on a quality gun to produce excellent patterns that we would expect from cylinder  through to full .in .410 ? 

Maybe it's just very hard to reproduce pattern size consistency from a .410 compared to 12b ? 

 

To get my Khan (Revo) OU multichoke 410 to shoot better, I got Briley extended tubes which were properly sized (originals were horrendously over choked) and have a post choke stability zone. This added about 10% to the pattern.

Substituting hard lead (high antimony 5%) added another 10%.

Reaming the forcing cones to 2 1\2 inches added another 5%.