Originally Posted by
TCinVA
Screw-in chokes allow you to tune the performance of your shotgun when firing actual shot loads (as in bird shot) so you can reliably bring down game. If you are shooting dove at 50 yards you're going to want a tighter choke to keep your pattern at that distance dense enough to hit the dove.
Conversely, if you are shooting a fast-flying clay pigeon at 15 yards that tight dove-killing pattern at 50 means you gave a much lower margin of error in hitting the clay.
So being able to change your choke is pretty useful if you are doing any sort of wing shooting with the shotgun.
Where a tighter choke helps tighten up the pattern of birdshot, it can have exactly the opposite effect on buckshot. One of the things that causes buckshot to spread is the contact that happens between pellets. This is why premium quality loads will have some sort of cushioning between pellets in the shell so they don't make as much impact into one another and flat spot. They will also use harder lead alloys and copper plating to make the pellet harder and resist deformation because it helps the pellet fly more true to point of aim.
Think of what would happen to a golf ball if you put it to a sander, flattened one edge out, and then whacked the ball with a driver. It would be comically inaccurate no matter how skilled the golfer who hit it was. Same sort of thing applies to pellets.
When they are fired, they make some level of contact. If they suddenly hit a severe constriction in the barrel then they're slammed into one another and the flat spots get larger and a sort of "billiard ball" effect is added to the whole affair which can make the resulting pattern a real shitshow.
Cylinder bore has typically been the standard for defensive use for this reason and to allow the use of slugs.
Now you can play with various combinations of buckshot loadings and chokes and you will likely find that some loads will actually perform better through a given barrel with an improved cylinder or modified choke. If you want to take that time and effort to try and find those combinations, rock on.
If you use ammunition with a flight control style wadding, tighter chokes can actually strip the wadding off the shot column sooner, giving you a less desirable pattern.
I wouldn't mind having a 1301T or 300UP with screw-in chokes, but primarily because I might want to take that gun and shoot the occasional bird or clay with it and the ability to put in a choke that enhances performance when wingshooting would be nice for that. But for defensive use I'm fine with a plain cylinder bore.