Some responses:
I have seen crooked chokes in all manner of barrels and brands, and figure that I could make money betting that at least 8 of 10 of any guns taken off the shelf would be crooked enough for me to spot by eye. When I saw that $7000 trap double O/U with obviously crooked chokes installed, nobody is safe.
BTW, shooting a barrel for POI is not going to tell you if the choke is actually straight, and one article that I posted at my website pointed out the details that I will not use time and space here to repeat, but suffice to say that shooting a screw-in choke will only tell you point of impact, not whether there is a concurrent alignment issue that hasn't been discovered by direct examination.
That is the same as driving a car and noticing that it does not pull or drift on the road and presuming the front end is aligned. Measuring on the front-end alignment machine is definitive, and the drive on the road by the mechanic is used AFTERWARD to verify the efficacy of the alignment.
Fixing a crooked choke is best done by starting with a hacksaw. If a hole is already in the barrel, there may not be enough meat left to enlarge the existing hole to the point of parallel alignment to fit some oversize tube or choke.
I have seen plenty of tools to install chokes that were claimed to allow perfect alignment and knew that the selling was based on rosy thinking, at best, or a bad case of not knowing what "perfect" meant- similar to the meaning of "is". Anybody making use of those same tools might think that they were doing shooters a service by altering barrels with tools meant to make the buyer into an instant choke expert. I believe that is about as sensible as buying a box of wrenches and expecting to become an instant mechanic.
I saw the inherent problems with those installation tool varieties and have totally avoided association with aftermarket chokes so there would be no guilt by association for myself. I can install my custom chokes where insufficient room remains for American pattern choke holes. Then I make and fit the choke specifically to the individual barrel.
I am not saying it is impossible to have an aftermarket choke installed straight, but that the number of possible bad installation possibilities made me leery of using any mass-production system. One detail for sure is that the mass-produced chokes have no barrel bore precision fit to the choke like my individually made and fitted tubes. I have too much precision fitting built into each choke to have any comparison to typical production chokes of any brand.
Those photos posted were of barrels cut off by me, and are by no means anywhere near the total of bad ones removed, just some sampling to give some variety and meaning. The camera doesn't necessarily need perfect centering to show obvious error, and you might note that even though I do know how to verify camera alignment, the first picture had the camera near the low edge to show the viewer how close the tube was to the bore edge.
Choke roundness and accuracy is not a normal issue, if talking within .002" or so, at least, but I have seen some that were farther off and some that varied in accuracy.
Chokes do not "wear" per se, but may be abused and distorted by heavy shot payloads or normal payloads if made from soft and/or defective materials. Any choke that I spot that has gone egg-shaped or out-of-round is not considered as a normal wear issue from normal use.
I am not referring to the subtleties associated with metal movement that must be addressed with gage-bloks and other highly accurate specimens, and choke movement at those minimal levels are left to theoretical discussions.
kirbythegunsmith@hotmail.com