Perhaps someone could enlighten readers on how fixed chokes are "opened." While it is obvious that some type of reamer is used, more detail would be appreciated.
1. Since shotgun bore sizes vary so much (12 gauge from .710 to .750 ?) the reamer probably has some mechanism to stay centered in the bore at the outset. How is this done? Guide bushings of various sizes; likely in the tool box but can be made rather easily. The more skilled the man the less guidance needed and the more likely to be used.
2. The choke reamer tool must be adjustable to cut a specific amount. How is that done? Adjustable reamers are common tooling.
3. Supposedly that last inch or so of the barrel should be the same parallel "new" diameter. How does the gunsmith cause that to happen? With a reamer or hone set to cut up to the desired new diameter. However, currently new data strongly suggests that the parallel is not needed, but does no harm either.
4. Is this reaming process performed from the breech/chamber end of the barrels using a long rod? Either works and depends on the craftsman's set-up and preference.
Hope this query isn't too basis.... Not at all too basic. I'd suggest you read "Performance of Sporting Shotguns" by Dr. Andrew Jones as his data on shotgun patterning is outstanding.
DDA
