I spent an hour or so yesterday checking and recording the throats on all my revolvers. I had done this before but over the years had used a variety of measuring techniques. This time I used the plug gauges only. Things pretty much followed what I expected especially the ones that had been worked on or converted by a custom gunsmith. The unexpected thing I ran into was on a couple of S&W revolvers.
On these some of the throats would only pass a smaller than expected gauge. On a whim, I inserted the plug from the chamber side. On a S&W Mod. 686 the .357 gauge would enter the throat up to the very mouth of the throat. It was almost like a uniform burr existed and about a couple of thousandths material prevented the plug from extending thru. To be clear, 3 throats measured .357 with the plug entering normally from the front. On 2, they would only accept a .356 plug and on 1, a .355 plug. This is the worst example.
These are guns that I bought used, although apparently shot very little. I would have assumed that with so little material at the mouth, shooting would have burned off a burr(?). Now I'm wondering if I need to have the throats reamed.
Thoughts? Should I send the cylinders to DougGuy for reaming?