I have a what I believe is a simple question. How much, if at all, do the machining marks inside of a CNC milled choke tube effect the performance of the tube. I’ve seen tubes that are mirror smooth, and others that have light milling marks, and some with heavier marks.
What’s the effect? Did I mention that I’m looking for additional excuses for my poor shooting?
I’ve noticed the same thing myself, particularly with Briley over-the-counter chokes. Some are smooth and some are rough inside.
You’d think that a rough choke was the sign of careless machining and that it was a flaw. I’m sure that the choke companies would prefer to make smooth chokes, but there really are two schools of thought on rough chokes.
By far the largest majority of makers feel that smooth chokes are the way to go. With only one exception that I know of, all makers of fixed choke guns make their chokes as smooth as their barrel bores. The “premium” screw choke makers also spend considerable time trying to get their screw chokes smooth inside. A quick glance down Rhinos or Teagues will show this.
The theory behind smooth chokes is that
1) it shows a “proper” gunmaking technique, and
2) smooth surfaces pick up less plastic and lead fouling.
No argument there. It’s also very much a perceived quality thing. Most shooters assume that a rough choke is a sign of poor quality and in most cases they are right.
There is contrary opinion. The theory is that a rough choke very slightly retards the wad and helps the shot and wad separate. This is supposed to produce more reliable patterns because, in theory, it keeps the wad from disrupting the shot cloud. Lujtic trap guns often have a scribed circle or two in the choke to act as a wad grabber. Pattern Master screw chokes have a series of knobs inside their chokes that are meant to aggressively strip the wad. The wads end up looking like they’ve been chewed by a doberman. Ported extended screw chokes (the porting also acts as a roughening procedure) are supposed to
1) reduce recoil and
2) act as a wad stripper.
Like anything, roughening can go to an extreme. One of the old tyme duck hunter’s myths was that your barrel would shoot tighter if you peed down the barrel and stood the gun in the corner for a week to rust (and thus roughen) the interior of the barrel.
Those are the two opposite theories. In my experience the only thing that rough chokes do is to collect plastic. It’s like a poor quality forcing cone job that isn’t smooth. It garbages up pretty quickly. I notice this stuff more than most people do because I generally “shoot my guns clean”. Translation: my cleaning regimen is shamefully slothful. After a while, my guns look like my office.
Like so much else in patterning, there are so many other variables that it’s hard to tell how much each one contributes to the overall end product. I’ve seen good patterns from roughly machined chokes and I’ve seen good ones from carefully machined chokes. But I’ve seen more good ones from well machined chokes.
Another thing to consider is that if the choke is rough (assuming that was not the intention of the manufacturer), what else is there that is wrong with the choke? Choke concentricity, or lack thereof, can have an important effect on patterns too. One thing that you definitely don’t want is a choke that isn’t in there straight.
Bottom line: unless the choke was intentionally roughened, I view a rough choke as a manufacturing flaw and become suspicious. Still, the bottom line to all this stuff is the same as it always has been. HOW DOES THE CHOKE PATTERN? Even if the choke is ugly as a mud fence, if it gives you the patterns you want and doesn’t junk up so much with plastic that patterns degrade, then it’s a good choke. Handsome is as handsome does.
The Technoid writing for Shotgun Report, LLC
(Often in error. Never in doubt.)