Effect of barrel length on choke tubes

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Hi All,

Another beginner question regarding barrel length and choke tubes.

I was out at the Aheia range yesterday for some trap with the new Silver, my brother's 870 and my dad's old CIL.
The Silver is a 26" barrel and had an improved cylinder choke, the 870 is a 28" barrel with an improved cylinder and the CIL is a 28" with an improved modified.
Of the three guns, the CIL and the 870 were the most effective at breaking clays into puffs of dust as opposed to large chunks. This could just be an aiming issue but does the 2" less barrel length have such an effect on shot pattern that I have to go down a choke size? The Silver's hits resulted in fewer, larger chunks which to me is indicative of less pellets on targets, meaning more dispersion.

The next time I go out I'm going to try the modified choke as a comparison but I was just wondering what your guys' experience is. Unfortunately I don't seem to have a place to pattern it properly at 40 yards to see the actual numbers.
 
Barrel length has no relation to choke and pattern density . barrel length will have a slight effect on velocity . your silver also has a back bored barrel ( slightly larger bore diameter ) than the other 2 guns . not all chokes a created equally even 2 chokes of the same constriction and maker will more than likely pattern differently . and as you said the point of impact may be different causing you to only be hitting the target with only a small percentage of the pattern .shoot it on a pattern board is the only way you will know .
 
The only thing a longer bbl does as far shot is scrubs the shot as I'd travels down the bore and deforms it making it out of round whitch in theory will cause pellets loose velocity and fall out of the pattern . This of coarse is all technical carb and really has very little to do with breaking targets. In will How ever come in to play if u are shooting from the 25yd-27yd pad in ata trap
 
Thanks for the replies.

I was just reading on the Remington and Browning sites about their claims for shot dispersions.
Remington claims 45-50% of shot within a 30" circle at 40 yards with an improved cylinder, while Browning claims 35-45%. I guess stepping up my choke will make their dispersions a bit more comparable.
 
You need to consider the distance that you are breaking the target at. The further away, the tighter the choke needs to be to throw the same pattern. General rule of thumb is that you need .005 more constriction to move the pattern out 5 yards. YMMV. Many of the old choke tubes are not accurate in their constriction nor are they very good at spreading the pellets evenly within the circle. The best way to determine what choke you have is to measure it with a bore gauge. You also need to pattern them on paper at the yardage that you are shooting (breaking) the target. Look for holes in the pattern that a target can fly through. Again, YMMV. An Improved Modified choke (.025) will smoke targets at 40 yards. An Improved Cylinder choke (.010) will not work well at 40 yards. If you are in fact, breaking the targets at 40 yards, I suspect the 870 choke is much tighter than .010 or it has a hot spot in the pattern.
 
Beretta687EELL said:
You need to consider the distance that you are breaking the target at. The further away, the tighter the choke needs to be to throw the same pattern. General rule of thumb is that you need .005 more constriction to move the pattern out 5 yards. YMMV. Many of the old choke tubes are not accurate in their constriction nor are they very good at spreading the pellets evenly within the circle. The best way to determine what choke you have is to measure it with a bore gauge. You also need to pattern them on paper at the yardage that you are shooting (breaking) the target. Look for holes in the pattern that a target can fly through. Again, YMMV. An Improved Modified choke (.025) will smoke targets at 40 yards. An Improved Cylinder choke (.010) will not work well at 40 yards. If you are in fact, breaking the targets at 40 yards, I suspect the 870 choke is much tighter than .010 or it has a hot spot in the pattern.
Click to expand...

You raise a really good point about distance. I was consistently faster at downing the clays compared to my dad and brother and therefore the Silver had less of a chance of significantly breaking the clay compared to the 870.
The only way to tell for sure is to do the pattern test and then just shoot quickly.
 
Now that you understand that 2 different choke tubes of the same constriction throw different patterns. Shell velocity effects patterns as well. As a general rule, but always the case, a faster velocity load will pattern tighter, but tends to produce more fliers. A 1oz load in 12ga, tends to pattern more even than a 1 1/8Oz, which tends to pattern more even than a 1 1/4Oz. Tapered forcing cones tend to pattern more even than abrupt ones. Longer chokes tend to produce more even patterns than short chokes. Whereas, these are trends they are not the gospel by any means. A pattern board, as always, will be your friend to determine what your gun is doing with your ammunition.
 
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RatFink said:
You raise a really good point about distance. I was consistently faster at downing the clays compared to my dad and brother and therefore the Silver had less of a chance of significantly breaking the clay compared to the 870.
The only way to tell for sure is to do the pattern test and then just shoot quickly.
Click to expand...
People shoot the same target at different places because they move at different speeds and see and react differently. To intentionally try and shoot the target faster is a recipe for disaster. As Maritime Storm mentioned, your gun will shoot a certain pattern with certain ammunition and basically the choke that is in your gun's barrel will theoretically move the effective pattern closer or further away from the muzzle based on how much constriction the choke tube has. Here is a link to the Briley Manufacturing web site where they do a better job of explaining chokes than I ... http://www.briley.com/understandingchokes.aspx
 
Well - As stated, trap generally requires a tighter choke than IC - most people use mod or full. Bear in mind that in shooting clays, a broken bird is a broken bird. Shoot a few rounds of trap with your IC choke, then do the same with a full choke, and report back to us.
 
'Imp Cyl' or whatever stamped on a barrel, is really only a guideline. Pattern percentage will change with shot size, brand of shot, hardness of shot, shot material, amount of shot, velocity of shot, style and make of wad, forcing cone, barrel diameter, and probably another couple I left out. Length, not so much.
 
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