View Full Version : open cylinder

March 9, 2008, 12:36 PM
I bought an 18" barrel for my 870, and it says in the ad (open cylinder, I am assuming that whatever shot i use will be wide spread right at the muzzle, am I right or wrong?:confused:

March 9, 2008, 01:16 PM
It won't be opened up any more than the wad and the diameter of the hole in the loud end. All shot paterns open up once they leve the bbl- some, as with extended ex-full chokes open up much much less than yours will in the same distance.

I think the only way to truely determine how your pattern behaves is to put it to the paper- 4x4 cardboards, box of shells, thermos of coffee, quality range time, friends, burnt powder... What could make life better?

March 9, 2008, 01:23 PM
10-96 is correct on all points.

"Open Cylinder" simply indicates that there is no bore restriction, i.e., "choke," at the muzzle. While there are no clear-cut standards for choke designations, e.g., how much restriction is an "Improved Cylinder" choke, Open Cylinder is exactly what it says, regardless of gauge or manufacturer: no choke at all.



March 9, 2008, 01:42 PM
Like 10-96 said, as with any shotgun and choke, it's important to pattern it at the range you would expect to use it. Even with an open (cylinder bore) choke, the pattern might not be as large as you would think at closer ranges.

March 9, 2008, 09:41 PM
As a "rule of thumb" an open cylinder bore gun will shoot a pattern that opens up "about" one inch per yard from the muzzle.

in other words, at 9 feet/3 yards the pattern will be "about" 3 to 4 inches in diameter.

March 10, 2008, 05:46 PM
cylinder bore?