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Just a quick answer to one question that has been asked a couple of times; does barrel length affect shot pattern.

If you have choke in the bore barrel length has no affect on pattern because the coke is measured at the target, not at the barrel.

HOWEVER

If there is no choke in the barrel does barrel length affect pattern???

From my crude test I must say that it does.

I happen to have a series of barrels of varying length that have cylinder bores. A quick trip to the pattern board gave me some good test patterns and I decided to post two.

These are not the normal 40 yard patterns. Both were shot at 25 yards, since I decided previously that a cylinder bore was pretty much useless at 40.

25 yards/75feet is about the top of most second growth trees and would be the outside range for squirrel shots. If one were really sneaky 25 yards is fair rabbit range.

The circle is 2 feet diameter. hey are labeled so you can tell for yourself that there is a definite difference between the even distribution of the 26" barrel and the ragged pattern with several open holes provided by the 18" barrel.

The 18 inch barrel is from a Remington 870 factory riot gun. The 26" barrel is from a Stevens shotgun that was trimmed some time in its past to remove the choke and shorten the barrel from 28".

One thing I did note was that all of the cylinder bore barrels shot off of the sights. They all shot high! Very high! To keep the patterns on the paper I was required to aim off the target at the bottom, and the patterns were still high.

Just reinforcement that one needs to pattern their guns before use. What seems like a bad miss by the shooter might be sights that need attention, such as a bigger bead or a bead on a ramp.

[Image: DSCF1326_zpsb0ge1xqr.jpg]

[Image: DSCF1325_zpsqtxbgxih.jpg]

Apparently the 26" barrel maintains the integrity of the shot column long enough to stabilize the load and give better distribution of the shot.

I personally do not feel that reducing the length of the barrel gives enough handling advantage to warrant the destruction of the efficiency of the gun. And if I have a 26" barrel I want some choke in it.
In barrels shorter than about 4 inches the muzzle pressure at shot exit is higher, which tends to open patterns if the shot are not contained in a plastic shot cup or wrapper.
Now remembering that you fellows are restricted to a 24" barrel, I pulled out my Mossberg slugger barrel, which is a smoothbore cylinder tube and just happens to be 24" long.

It also has a nice set of sights on it with a rear sight that flips up or down to suit your need.

And as one might expect, it sort of performed between the 18 and 26 inch lengths. There is a nice smooth distribution on the center and at the edges there are some disturbing holes.

If I were using this one on a regular basis I would adjust the sights to place that nice thick part of the pattern at the POA and live with it.

[Image: DSCF1327_zpszkc04gn5.jpg]
CORRECTION -- TWENTY FOUR INCHES! fumble fingers on tiny phone keypad!
Oh yes, that big hole on the right bottom of the paper is the plastic wad, that was still traveling fast enough at 25 yards to pop a hole in the paper.

Now this is just for the reference records, so if you ever get asked, or need to compare for decision making it's there for you.

The general moral of the story being when it comes to open choke, the longer the barrel the better.

I also have an open choke barrel that I did a "jug choke" on. I found that it does work, and I closed the pattern from 30% to close to 45%, but it was a crap load of work and took some specialized tools. You are not going to do it with a dowel and sandpaper no matter what the guy on you-tube said.

BTW these were factory shells with plastic shot wads and cups. 1oz. of 7 1/2 chilled lead shot. All from the same box.